﻿The Project Gutenberg EBook of Natural Gemstones, by Various

This eBook is for the use of anyone anywhere in the United States and most
other parts of the world at no cost and with almost no restrictions
whatsoever.  You may copy it, give it away or re-use it under the terms of
the Project Gutenberg License included with this eBook or online at
www.gutenberg.org.  If you are not located in the United States, you'll have
to check the laws of the country where you are located before using this ebook.

Title: Natural Gemstones

Author: Various

Release Date: January 16, 2015 [EBook #47999]

Language: English

Character set encoding: UTF-8

*** START OF THIS PROJECT GUTENBERG EBOOK NATURAL GEMSTONES ***




Produced by Stephen Hutcheson, Dave Morgan, Carol Spears
and the Online Distributed Proofreading Team at
http://www.pgdp.net






[Illustration: Quartz, Rhode Island.]

[Illustration: Amethyst crystals, Mexico.]




U.S. Department of the Interior
U.S. Geological Survey




                                Natural
                               Gemstones


Searching for gemstones in the United States is a popular recreational
activity for collectors and hobbyists




                           Natural gemstones


A _natural gemstone_ is a mineral, stone, or organic matter that can be
cut and polished or otherwise treated for use as jewelry or other
ornament. A precious gemstone has beauty, durability, and rarity,
whereas a semiprecious gemstone has only one or two of these qualities.
A _gem_ is a gemstone that has been cut and polished.

Diamond, corundum (ruby and sapphire), beryl (emerald and aquamarine),
topaz, and opal are generally classed as precious stones. All other
gemstones are usually classed as semiprecious.

A _mineral_ is any naturally formed homogeneous inorganic material.

A _mineralogist_ is a person who studies the formation, occurrence,
properties, composition, and classification of minerals.

A _gemologist_ is a person who has successfully completed recognized
courses in gemology (the science and study of gemstones) and has proven
skills in identifying and evaluating gem materials.

A _lapidary_ is a cutter, polisher, or engraver of precious stones.


                          Geologic environment

Gemstones are not plentiful. Gemstones do not form “ore” deposits in the
normal sense.

Gems, when present at all, tend to be scattered sparsely throughout a
large body of rock or to have crystallized as small aggregates or fill
veins and small cavities.

Even stream gravel concentrations tend to be small—a few stones in each
of several bedrock cracks, potholes, or gravel lenses in a stream bed.

The average grade of the richest diamond kimberlite pipes in Africa is
about 1 part diamond in 40 million parts “ore.” Kimberlite, a plutonic
igneous rock, ascends from a depth of at least 100 kilometers (60 miles)
to form a diatreme (narrow cone-shaped rock body or “pipe”). Moreover,
because much diamond is not of gem quality, the average stone in an
engagement ring is the product of the removal and processing of 200 to
400 million times its volume of rock.


          Gemstones occur in most major geologic environments.

Each environment tends to have a characteristic suite of gem materials,
but many kinds of gems occur in more than one environment. Most
gemstones are found in igneous rocks and alluvial gravels, but
sedimentary and metamorphic rocks may also contain gem materials.

Examples of geologic environments in which gemstones are found:

_Pegmatite_—a coarse-grained intrusive igneous rock body, occurring as
dikes (a tabular-shaped body), lenses, or veins in the surrounding rock.

_Stream gravels_ (_placers_)—deposits of heavier and more durable than
average minerals that have been eroded out of the original rock. Often
tourmaline, beryl, and many other gem-quality minerals have eroded out
of the original rock in which they formed and have moved and been
concentrated locally by water in streams. Sapphires in Judith Basin
County, Montana, were first found when the gravels were worked for gold
from 1895 to 1930.

_Metamorphic rocks_—rocks that have been altered by great heat,
pressure, or both. Garnet, for example, is commonly found as crystals in
gneiss and mica schist.

[Illustration: Quartz with phantoms, Brazil.]

[Illustration: Aquamarine, Brazil.]


                           Mineral gemstones

Hardness and specific gravity are two of the major characteristics of
gemstones.

Hardness of a gemstone is its resistance to scratching and may be
described relative to a standard scale of 10 minerals known as the Mohs
scale. F. Mohs, an Austrian mineralogist, developed this scale in 1822.

According to Mohs’ scale, the hardness of—

  Talc is              1
  Gypsum is            2
  Calcite is           3
  Fluorite is          4
  Apatite is           5
  Feldspar is          6
  Quartz is            7
  Topaz is             8
  Sapphire is          9
  Diamond is          10

Specific gravity is the number of times heavier a gemstone of any volume
is than an equal volume of water; in other words, it is the ratio of the
density of the gemstone to the density of water.

_The 16 mineral gemstone groups listed below are highly prized for their
beauty, durability, and rarity_:

  Beryl (hardness: 7.5-8 Mohs)
  Beryllium aluminum silicate
  Specific gravity: 2.63-2.91

  _Emerald_: Intense green or bluish green
  _Aquamarine_: Greenish blue or light blue
  _Morganite_: Pink, purple pink, or peach
  _Heliodore_: Golden yellow to golden green
  _Red beryl_: Raspberry red
  _Goshenite_: Colorless, greenish yellow, yellow green, brownish

  Chrysoberyl (hardness: 8.5 Mohs)
  Beryllium aluminum oxide
  Specific gravity: 3.68-3.78

  _Chrysoberyl_: transparent yellowish green to greenish yellow and pale
              brown
  _Alexandrite_: red in incandescent light and green in daylight
  _Cat’s eye_: usually yellowish or greenish

  Corundum (hardness: 9 Mohs)
  Aluminum oxide
  Specific gravity: 3.96-4.05

  _Ruby_: Intense red
  _Sapphire_: Blue

  Diamond (hardness: 10 Mohs)
  Carbon
  Specific gravity: 3.51

  Colorless to faint yellowish tinge, also variable

  Feldspar (hardness: 6-6.5 Mohs)
  Two distinctly different alkali alumino silicates: the Plagioclase and
              the Alkali Feldspar Series
  Specific gravity: 2.55-2.76

  Plagioclase Series—
  _Labradorite_: Colorful, iridescent, also transparent stones in
              yellow, orange, red, and green
  _Sunstone_: Gold spangles from inclusions of hematite
  _Peristerite_: Blue white iridescence

  Alkali Feldspar Group—
  _Orthoclase_: Pale yellow, flesh red
  _Amazonite_: Yellow green to greenish blue
  _Moonstone_: Colorless; also white to yellowish, and reddish to bluish
              gray

  Garnet (hardness: 6.5-7.5 Mohs)
  A group of silicate minerals
  Specific gravity: 3.5-4.3

  _Almandine_: Orangy red to purplish red
  _Almandine-spessartine_: Reddish orange
  _Andradite_: Yellowish green to orangy yellow to black
    _Demantoid_: Green to yellow green andradite
    _Topazolite_: Yellow to orangy yellow
  _Grossular_: Colorless; also orange, pink, yellow, and brown
    _Tsavorite_: Green to yellowish green
    _Hessonite_: Yellow orange to red
  _Pyrope_: Colorless; also pink to red
    _Chrome pyrope_: Orange red
  _Pyrope-Almadine_: Reddish orange to red purple
  _Pyrope-Spessartine_: Greenish yellow to purple
    _Malaia_: Yellowish to reddish orange to brown
    _Color-change garnet_: Blue green in daylight to purple red in
              incandescent light
  _Rhodolite_: Purplish red to red purple
  _Spessartine_: Yellowish orange
  _Uvarovite_: Emerald green

  Jade (hardness: 6 Mohs)

  _Nephrite_
  Calcium magnesium silicate
  Specific gravity: 2.9-3.1

  White, deep green, creamy brown

  _Jadeite_
  Sodium aluminum silicate
  Specific gravity: 3.1-3.5

  White, leafy and blue green, emerald green, lavender, dark blue green
              and greenish black, deep emerald-green

  Lapis lazuli (hardness: 5-5.5 Mohs)
  A rock composed mainly of the mineral lazurite with variable amounts
              of pyrite (brassy flecks) and white calcite
  Specific gravity: 2.7-2.9

[Illustration: Diamond Star of Sierra Leone.]

  Deep blue, azure blue, greenish blue (bluish color with flecks of
              white and gold)

  Opal (hardness: 5.5-6.5 Mohs)
  Hydrated silica
  Specific gravity: 1.98-2.25

  _White opal_: Opaque, porcelain-like white material; colors resemble
              flashes or speckles
  _Black opal_: Flashes and speckles appear against black background
  _Water opal_: A transparent, colorless opal is the background for
              brilliant flashes of color
  _Fire opal_: Reddish or orange opal

  Peridot [Olivine] (hardness: 7 Mohs)
  Magnesium iron silicate
  Specific gravity: 3.22-3.45

  Olive to lime green

  Quartz (hardness: 7 Mohs)
  Silicon dioxide or silica
  Specific gravity: 2.65

  Coarsely crystalline varieties of silica—
  _Rock crystal_: Colorless
  _Amethyst_: Purple
  _Citrine_: Yellow to amber
  _Morion_: Black
  _Smoky quartz or cairngorm_: smoky gray to brown
  _Rose quartz_: Translucent pink
  _Green quartz or praziolite_: Green

  Cryptocrystalline varieties of silica—
  _Chalcedony and Jasper_ (_variable_)
  _Agate_: Bull’s eye agate, Iris or fire agate, Onyx, Sardonyx.
  _Bloodstone or heliotrope._ _Carnelian._ _Chrysoprase._ _Moss agate._
              _Plasma._ _Prase._ _Sard._ _Jasper._

  Spinel (hardness: 8 Mohs)
  Magnesium aluminum oxide
  Specific gravity: 3.58-4.06

  _Balas ruby_: Red
  _Almandine spinel_: Purple red
  _Rubicelle_: Orange
  _Sapphire spinel and ghanospinel_: Blue
  _Chlorspinel_: Green

[Illustration: Candelabra: white quartz, blue-capped red elbaite, and
tan albite, California.]

  Topaz (hardness: 8 Mohs)
  Aluminum silicate fluoride hydroxide
  Specific gravity: 3.5-3.6

  Wine yellow, pale blue, green, violet, or red

  Tourmaline (hardness: 7-7.5 Mohs)
  Complex aluminum borosilicate (Elbaite, Dravite, Uvite)
  Specific gravity: 3.03-3.25

  _Achorite_: Colorless
  _Brazilian emerald_: Green
  _Dravite_: Brown
  _Indicolite_: Dark blue
  _Rubellite_: Pink to red
  _Siberite_: Violet
  _Verdilite_: Green

  Turquoise (hardness: 5-6 Mohs)
  Hydrous copper aluminum phosphate
  Specific gravity: 2.6-2.8

  Sky blue; greenish blue

  Zircon (hardness: 7.5 Mohs)
  Zirconium silicate
  Specific gravity: 4.6-4.7

  _Jargon_: Variable
  _Matura diamond_: Colorless
  _Hyacinth_: Yellow, orange, red, brown

[Illustration: The Hooker Emerald, Colombia.]


                              Birthstones

  Month of birth    Gemstone                            Color
  January           Garnet                              Dark red
  February          Amethyst (Quartz)                   Purple
  March             Aquamarine (Beryl) or Bloodstone    Pale blue
                    (Quartz)
  April             Diamond or Rock Crystal (Quartz)    Colorless
  May               Emerald (Beryl)                     Bright green
                    or Chrysoprase (Quartz)             Pale green
  June              Pearl or Moonstone (Feldspar)       Cream
  July              Ruby (Corundum) or Carnelian        Red
                    (Quartz)
  August            Peridot                             Pale green
                    or Sardonyx (Quartz)                Brown and white
  September         Sapphire (Corundum)                 Pale to dark blue
                    or Lapis Lazuli                     Deep blue
  October           Opal or Tourmaline                  Variegated
  November          Topaz or Citrine (Quartz)           Yellow
  December          Turquoise                           Sky blue


                           Organic gemstones

The four organic gemstone groups listed below are highly prized for
their beauty and rarity. However, they are not as durable as gemstones
from minerals:

  Amber (hardness: 2-2.5 Mohs)
  A mixture of hydrocarbons
  Specific gravity: 1.05-1.096

Hard fossil resin or sap of ancient pine trees. Usually amorphous (lacks
crystalline structure). Sometimes mined, sometimes gathered on
seashores.

Varies from transparent to semitransparent and generally from light
yellow to dark brown, but can be orange, red, whitish, greenish-brown,
blue, or violet. Can be dyed in any color.

Takes a fine polish. Used mainly in making beads or other ornaments.

  Coral (hardness: 3.5-4 Mohs)
  Formed mainly of calcite (calcium carbonate) or conchiolin, a horny
              organic substance
  Specific gravity: 2.60-2.70

Each coral polyp, a tiny marine animal that lives in enormous colonies,
extracts calcium carbonate from the sea and exudes it to build a
protective home around and above itself. Each generation of polyps dies
in its protective home and each succeeding generation builds on top of
its predecessor.

Gem coral ranges from semitranslucent to opaque and occurs in white,
pink, orange, red, blue, violet, golden, and black. The black and golden
corals are largely horny organic substances, not calcium carbonate.

The finest coral is used to make figurines, cameos, carvings, and beads.

  Jet (hardness: 2.5-4 Mohs)
  Carbon plus various hydrocarbon compounds
  Specific gravity: 1.30-1.32

This compact velvet-black coal takes a good polish and is often cut into
beads, bracelets, and a wide range of decorative and useful objects.

  Pearl (hardness: 2.5-4.5 Mohs)
  Formed within a mollusk, such as an oyster, that deposits a substance
              called _nacre_ around an irritant that entered the
              organism
  Specific gravity: 2.71

Pearl-bearing mollusks are found in both salt and fresh water.
Salt-water pearls of gem quality are usually preferred for jewelry; they
are produced almost entirely by the mollusk _Pinctada_. Fresh-water
pearls are produced by various clams and mussels.

Natural pearls come in various shapes: round, pear, drop, egg, and
others. They also come in various colors, such as white, cream, light
rose, cream rose, black, gray, bronze, blue, dark blue, blue green, red,
purple, yellow, and violet.


                              Buyer beware

Inexperienced buyers must take whatever steps are needed to ensure that
gems they intend to purchase are exactly what the seller purports them
to be and that they are being offered at a fair market price.

More and more synthetic gems—and inferior grades and cuts of natural
gems—are being sold to unwary buyers by unscrupulous sellers.


   Since 1935, the mining of gemstones in the United States has been
almost entirely a recreational activity of mineral collectors and hobbyists.

In recent years, very few individuals have derived their entire income
from gemstones mined by themselves.

This is not to say that the proprietors of roadside rock shops buy all
of their stock from others. Rock shops are abundant in areas of the
United States that are rich in gem materials, and the shops tend to
specialize in the local gem commodities, most of which the proprietors
gather.

Rather than doing the mining themselves, owners of land that has a
deposit of gem-quality minerals sometimes charge hobbyists for the right
to collect gemstones. For example, diamond in Arkansas, opal in Idaho,
and agate in Oregon and Washington are mined by hobbyists under this
“fee digging” arrangement.

However, the flow of money into the local economy by paying these small
fees and by the purchase of gemstones is minor compared to the money the
enthusiasts spend for lodging and other living expenses while visiting
an area to dig for gemstones.

Several kinds of natural gemstones have been found in every State of the
United States, but much larger deposits of the most precious kinds are
found outside the United States.


The 1990 U.S. output of natural gemstones was primarily from Tennessee,
       California, Arizona, Arkansas, Montana, Nevada, and Maine.

An estimated 80,000 visitors found a total of 315 carats of diamonds in
the Crater of Diamonds State Park in Arkansas. There were sizeable
yields of freshwater pearls in Tennessee, turquoise in Arizona and
Nevada, tourmaline in Maine, and tourmaline, kunzite, and garnet in
California.


   Gemstones: Value of U.S. production vs. imports, 1986 and 1989[1]

  Production                          1986           1989
  Natural                             $9.3 million  $43.0 million[2]
  Synthetic                           10.3           23.5
                                     $19.6          $66.5
  Mine employment                      300            800
  Imports for consumption:           $4.18 billion  $5.00 billion
  Apparent reliance on imports over    99%            98%
      exports[3]


[1]Estimated.

[2]Including freshwater pearls natural, and cultured.

[3]Imports - exports + adjustments for Government and industry stock
    changes. Source: _Mineral Commodity Summaries_, 1991, U.S. Bureau of
    Mines.


U.S. production of commercial gems includes agate, beryl, freshwater
pearl, garnet, jade, jasper, mother-of-pearl, opal, peridot, quartz,
sapphire, tourmaline, and turquoise.


   Except for the few gem diamonds found each year in Arkansas, U.S.
                    diamond production is very low.

Yet exploration for diamonds continues in Alaska, Colorado, Michigan,
Minnesota, Wisconsin, and Wyoming. A diamond mining project at the
Crater of Diamonds State Park in Arkansas is still being evaluated by
the State.


  World diamond reserves are estimated to be about 300 million carats,
   including near-gem materials but not diamonds of abrasive quality.

Most of the reserves are in southern Africa, Siberia, and western
Australia. It is difficult to estimate reserves because the value of a
given deposit varies with the market for the gems.

[Illustration: Jade nephrite, China.]

[Illustration: The Hope Diamond, India.]


                     Chemical formulas of gemstones

  Beryl               BeࠣAlࠢSiࠦO₁ࠨ
  Chrysoberyl         BeAlࠢOࠤ
  Coral               CaCOࠣ
  Corundum            AlࠢOࠣ
  Diamond             C
  Feldspar            Plagioclase Series:
                      (Na,Ca)Al(Al,Si)SiࠢOࠨ
                      Alkali Feldspar Group:
                      Mixtures of Orthoclase—KAlSiࠣOࠨ and
                      Albite—NaAlSiࠣOࠨ
  Garnet              Almadine—FeࠣAlࠢ(SiOࠤ)ࠣ
                      Andradite—CaࠣFeࠢ(SiOࠤ)ࠣ
                      Grossular—CaࠣAlࠢ(SiOࠤ)ࠣ
                      Pyrope—MgࠣAlࠢ(SiOࠤ)ࠣ
                      Spessartine—MnࠣAlࠢ(SiOࠤ)ࠣ
                      Uvarovite—CaࠣCrࠢ(SiOࠤ)ࠣ
  Jade                Nephrite—Caࠢ(Mg,Fe)ࠥ(SiࠨOࠢࠢ) (OH)ࠢ
                      Jadeite—NaAl(SiࠢOࠦ)
  Lapis lazuli        Lazurite—(Na,Ca)ࠨ(AlSiOࠤ)ࠦ (SOࠤ,S,Cl)ࠢ
  Opal                Hydrated Silica—SiOࠢ·_n_HࠢO
  Peridot             (Mg,Fe)ࠢ(SiOࠤ)
  Quartz              SiOࠢ
  Spinel              MgAlࠢOࠤ
  Topaz               AlࠢSiOࠤ(F,OH)ࠢ
  Tourmaline          XYࠣAlࠦ(BOࠣ)ࠣ(SiࠦO₁ࠨ) (OHࠤ)
                      [X is usually Na but may be replaced by Ca;
                      Y is one of several metal ions]
  Turquoise           CuAlࠦ(POࠤ)ࠤ(OH)ࠨ·4HࠢO
  Zircon              ZrSiOࠤ


        Some ways to contact a local rock, mineral, or gem club

If you have access to the most recent April Buyer’s Guide issue of the
_Lapidary Journal_ magazine, scan its lists of gem and mineral clubs in
the United States and other countries. (The address of the _Lapidary
Journal_ is given in the list of journals cited below.)

Talk to a member of the geology or earth science department of your
local college or university.

Talk to a member of the science department of your local high school.

Write to the—

  Eastern Federation of Mineralogical and Lapidary Societies
  Box 10119
  Alexandria, VA 22310-0119

or the

  Midwest Federation of Mineralogical and Geological Societies
  306 Somonauk
  Park Forest, IL 60466

Check the phone book for your nearest rock and mineral shop and talk to
the owners.


               Role of the U.S. Geological Survey (USGS)

The USGS reports deposits that seem likely to contain gemstones. It is
not a function of the USGS to exploit such resources.

USGS geologists perform continuing research on kimberlites, the initial
source of diamonds. Not all kimberlites are diamond-bearing, and some of
the research is directed to learning what indications you look for
during exploration to distinguish fertile from barren kimberlite. USGS
geologists are compiling a U.S. map showing the locations of known
kimberlites.


                      Selected general references

A trip to your local library is the best first step toward understanding
gemstones and toward planning a trip to gem and rock shops or to places
where you may be able to collect gemstones.

A list of _Selected references on rocks, minerals, and gemstones_ is
compiled and updated every two years by the USGS Geologic Inquiries
Group, 907 National Center, Reston, VA 22092; (703) 648-4383. The list
has three sections: selected guides for rockhounds and hobbyists,
general references for all ages, elementary school to adult, and
periodicals.

The guides in Section I tell about equipment needed for collecting,
etiquette of collecting, map reading, organizing a collection,
collecting localities by States, mineral societies, mineral show dates
and locations, and rock, mineral, and fossil dealers.

The references below focus mainly on natural gemstones and the gems made
from them rather than on synthetic gemstones, rocks, or other nongem
minerals.


_Minerals Yearbook_

The relatively few pages on gemstones in the multivolume _Minerals
Yearbook_ provide data on sources, kinds, and volume of domestic
production, domestic consumption, prices, and foreign trade. This U.S.
Bureau of Mines yearbook is in the reference sections of many major
libraries. It can be purchased from the Superintendent of Documents,
U.S. Government Printing Office, Washington, DC 20402.


_Books_

_Gemology_, Cornelius S. Hurlbut Jr. and Robert C. Kammerling: John
Wiley & Sons, New York, 1991, 2nd ed.

_Gemstones and Their Origins_, Peter C. Keller: Van Nostrand Reinhold,
1990.

_Color Encyclopedia of Gemstones_, Joel Arem: Van Nostrand Reinhold, New
York, 1987, 2nd ed., 68 p.

_Gemstones for Everyman_, B.W. Anderson: Van Nostrand Reinhold, 1976,
268 p.

_Gems and Precious Stones_, Curzio Cipriani and Alessandro Boreli;
Valerie Palmer, translator: Kennie Lyman, U.S. editor: Simon and
Schuster, New York, 1986, 384 p.

_Gem and Crystal Treasures_, Peter Bancroft: Mineralogical Record,
Carson City, NV, 1984, 488 p.

_Planet Earth—Gemstones_, Paul O’Neil and the editors of Time-Life
Books: Time-Life Books, Arlington, VA, 1983, 176 p.

_Gemstones of the World_, Walter Schumann (translated by Evelyne Stern):
Sterling, New York, 1984, 256 p.

_Gems & Crystals from the American Museum of Natural History: An
illustrated guide to the history, lore, and properties of the gems and
minerals of one of the world’s greatest collections_, Anna S. Sofiandes
and George E. Harlow: Simon & Schuster, New York, 1990, 208 p.

_The Gem Collection_ (Treasures in the Smithsonian Series No. 1), P.E.
Desautels: Smithsonian Institution, Washington, 1983, 77 p.

_Gemstones of North America_, John Sinkankas: D. Van Nostrand Company,
Inc., Princeton, 1959, 675 p.

_Gems and Precious Stones of North America—A popular description of
their occurrence, value, history, archeology, and of collections in
which they exist_, G.F. Kunz: Dover Publishing, New York, 1968 (reprint
of a classic work dated 1892), 367 p.

_Emerald and Other Beryls_, John Sinkankas: Chilton Way, Radnor, PA,
1981, 665 p.

_Handbook of Gem Identification_, R.T. Liddicoat Jr.: Gemological
Institute of America, Santa Monica, CA, 1981 (11th ed.), 450 p.

_Field Collecting Gemstones and Minerals_, John Sinkankas: Geoscience
Press, Prescott, AZ, 1988, 2nd ed., 397 p.

_Prospecting for Gemstones and Minerals_ [Formerly _Gemstones and
Minerals: How and Where to Find Them_], John Sinkankas: Van Nostrand
Reinhold, New York, 1970, 2nd ed., 397 p.

_Mineral & Gem Trails of Delaware, Virginia, Maryland, North Carolina_,
Ed and Bert Sloan: EDSCO, Box 79, Oneonta, NY 13820, 1978, 52 p.

_Gem Testing_, B.W. Anderson: Butterworth, Woburn, MA, 1980, 9th ed.,
384 p.

_Gemology_, C.S. Hurlbut Jr. and G.S. Switzer: Wiley, New York, 1979,
596 p.

_Gems and Jewelry_, Joel Arem: Bantam Books, New York, 1975, 159 p.

_Gem Cutting: A Lapidary’s Manual_, John Sinkankas: Van Nostrand
Reinhold, New York, 1962, 2nd ed., 297 p.

[Illustration: Lavender-hued rose quartz, Brazil.]


_Journals_

_Gems and Gemology_ (quarterly). Articles on gemstone localities,
identification, and history. Includes annual index, lab notes, book
reviews, and gemological abstracts. Published by the Gemological
Institute of America, 1660 Stewart Street, Santa Monica, CA 90404.

_Lapidary Journal_ (monthly). Articles on gemstones, locality
information, expeditions to find sources of gemstones, gemcraft, club
news, show news, product news, and book reviews. Published by the
Lapidary Journal, Devon Office Center, Suite 201, 60 Chestnut Avenue,
Devon, PA 19333-1312.

_Rocks & Minerals_ (bimonthly). Features articles of interest to
students of mineralogy, geology, and paleontology. Includes articles
about gemstone localities. Regularly lists announcements of hundreds of
mineral, rock, and gem shows (local, State, national, Canadian, and
European). Includes media reviews, museum notes and announcements, and
classified ads. Published by Heldref Publications, 4000 Albermarle
Street, NW., Washington, DC 20016.

_Jewelers’ Book Club—Catalog_ (annual). Catalog of more than 550
jewelry-related publications from more than 250 publishers. Includes
video- and audio-cassettes and book reviews. _Jewelers’ Book Club—News_
(quarterly) informs members of new titles and provides book reviews.
Published by the Jewelers Book Club, Chilton Way, Radnor, PA 19089.


_Videocassettes_

_Gemstones of America_ (60 minutes), Smithsonian Institution, 1991, can
be ordered for $29.95 from the Museum Shop, Attention: Mail Order Clerk,
National Museum of Natural History, 10th Street and Constitution Avenue,
NW., Washington, DC 20560; (202) 357-1535.

_Splendid Stones._ This National Geographic Society special details the
evolution from raw material to cut and polished gem, outlines many of
the steps involved in marketing gemstones, and examines some of the
world’s most famous jewelry collections. It can be ordered for $95 from
the National Geographic Society, 17th and M Streets NW., Washington, DC
20036.


                            Acknowledgments

The U.S. Geological Survey is grateful to the following individuals for
their assistance:

Harvey E. Belkin, Geologist, Geological Survey, U.S. Department of the
Interior, Reston, VA.

Gordon T. Austin, “Gem Stones,” _Mineral Commodity Summaries 1991_,
Bureau of Mines, U.S. Department of the Interior, Washington, DC.

Robert E. Thaden, “Gem Stones,” in _United States Mineral Resources_,
Geological Survey Professional Paper 820, U.S. Government Printing
Office, Washington, 1973, p. 247-250.

Jane Jenness, Minerals Information Office, U.S. Geological Survey,
Washington, DC.


                              Photographs

All photographs are courtesy of The Smithsonian Institution.




                          Transcriber’s Notes


--Retained publication information from the printed edition: this eBook
  is public-domain in the country of publication.

--In the text versions only, text in italics is delimited by
  _underscores_.

--In the ASCII version only, subscripted numbers are preceded by
  underscore and delimited by brackets.







End of the Project Gutenberg EBook of Natural Gemstones, by Various

*** END OF THIS PROJECT GUTENBERG EBOOK NATURAL GEMSTONES ***

***** This file should be named 47999-0.txt or 47999-0.zip *****
This and all associated files of various formats will be found in:
        http://www.gutenberg.org/4/7/9/9/47999/

Produced by Stephen Hutcheson, Dave Morgan, Carol Spears
and the Online Distributed Proofreading Team at
http://www.pgdp.net

Updated editions will replace the previous one--the old editions will
be renamed.

Creating the works from print editions not protected by U.S. copyright
law means that no one owns a United States copyright in these works,
so the Foundation (and you!) can copy and distribute it in the United
States without permission and without paying copyright
royalties. Special rules, set forth in the General Terms of Use part
of this license, apply to copying and distributing Project
Gutenberg-tm electronic works to protect the PROJECT GUTENBERG-tm
concept and trademark. Project Gutenberg is a registered trademark,
and may not be used if you charge for the eBooks, unless you receive
specific permission. If you do not charge anything for copies of this
eBook, complying with the rules is very easy. You may use this eBook
for nearly any purpose such as creation of derivative works, reports,
performances and research. They may be modified and printed and given
away--you may do practically ANYTHING in the United States with eBooks
not protected by U.S. copyright law. Redistribution is subject to the
trademark license, especially commercial redistribution.

START: FULL LICENSE

THE FULL PROJECT GUTENBERG LICENSE
PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK

To protect the Project Gutenberg-tm mission of promoting the free
distribution of electronic works, by using or distributing this work
(or any other work associated in any way with the phrase "Project
Gutenberg"), you agree to comply with all the terms of the Full
Project Gutenberg-tm License available with this file or online at
www.gutenberg.org/license.

Section 1. General Terms of Use and Redistributing Project
Gutenberg-tm electronic works

1.A. By reading or using any part of this Project Gutenberg-tm
electronic work, you indicate that you have read, understand, agree to
and accept all the terms of this license and intellectual property
(trademark/copyright) agreement. If you do not agree to abide by all
the terms of this agreement, you must cease using and return or
destroy all copies of Project Gutenberg-tm electronic works in your
possession. If you paid a fee for obtaining a copy of or access to a
Project Gutenberg-tm electronic work and you do not agree to be bound
by the terms of this agreement, you may obtain a refund from the
person or entity to whom you paid the fee as set forth in paragraph
1.E.8.

1.B. "Project Gutenberg" is a registered trademark. It may only be
used on or associated in any way with an electronic work by people who
agree to be bound by the terms of this agreement. There are a few
things that you can do with most Project Gutenberg-tm electronic works
even without complying with the full terms of this agreement. See
paragraph 1.C below. There are a lot of things you can do with Project
Gutenberg-tm electronic works if you follow the terms of this
agreement and help preserve free future access to Project Gutenberg-tm
electronic works. See paragraph 1.E below.

1.C. The Project Gutenberg Literary Archive Foundation ("the
Foundation" or PGLAF), owns a compilation copyright in the collection
of Project Gutenberg-tm electronic works. Nearly all the individual
works in the collection are in the public domain in the United
States. If an individual work is unprotected by copyright law in the
United States and you are located in the United States, we do not
claim a right to prevent you from copying, distributing, performing,
displaying or creating derivative works based on the work as long as
all references to Project Gutenberg are removed. Of course, we hope
that you will support the Project Gutenberg-tm mission of promoting
free access to electronic works by freely sharing Project Gutenberg-tm
works in compliance with the terms of this agreement for keeping the
Project Gutenberg-tm name associated with the work. You can easily
comply with the terms of this agreement by keeping this work in the
same format with its attached full Project Gutenberg-tm License when
you share it without charge with others.

1.D. The copyright laws of the place where you are located also govern
what you can do with this work. Copyright laws in most countries are
in a constant state of change. If you are outside the United States,
check the laws of your country in addition to the terms of this
agreement before downloading, copying, displaying, performing,
distributing or creating derivative works based on this work or any
other Project Gutenberg-tm work. The Foundation makes no
representations concerning the copyright status of any work in any
country outside the United States.

1.E. Unless you have removed all references to Project Gutenberg:

1.E.1. The following sentence, with active links to, or other
immediate access to, the full Project Gutenberg-tm License must appear
prominently whenever any copy of a Project Gutenberg-tm work (any work
on which the phrase "Project Gutenberg" appears, or with which the
phrase "Project Gutenberg" is associated) is accessed, displayed,
performed, viewed, copied or distributed:

  This eBook is for the use of anyone anywhere in the United States and
  most other parts of the world at no cost and with almost no
  restrictions whatsoever. You may copy it, give it away or re-use it
  under the terms of the Project Gutenberg License included with this
  eBook or online at www.gutenberg.org. If you are not located in the
  United States, you'll have to check the laws of the country where you
  are located before using this ebook.

1.E.2. If an individual Project Gutenberg-tm electronic work is
derived from texts not protected by U.S. copyright law (does not
contain a notice indicating that it is posted with permission of the
copyright holder), the work can be copied and distributed to anyone in
the United States without paying any fees or charges. If you are
redistributing or providing access to a work with the phrase "Project
Gutenberg" associated with or appearing on the work, you must comply
either with the requirements of paragraphs 1.E.1 through 1.E.7 or
obtain permission for the use of the work and the Project Gutenberg-tm
trademark as set forth in paragraphs 1.E.8 or 1.E.9.

1.E.3. If an individual Project Gutenberg-tm electronic work is posted
with the permission of the copyright holder, your use and distribution
must comply with both paragraphs 1.E.1 through 1.E.7 and any
additional terms imposed by the copyright holder. Additional terms
will be linked to the Project Gutenberg-tm License for all works
posted with the permission of the copyright holder found at the
beginning of this work.

1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm
License terms from this work, or any files containing a part of this
work or any other work associated with Project Gutenberg-tm.

1.E.5. Do not copy, display, perform, distribute or redistribute this
electronic work, or any part of this electronic work, without
prominently displaying the sentence set forth in paragraph 1.E.1 with
active links or immediate access to the full terms of the Project
Gutenberg-tm License.

1.E.6. You may convert to and distribute this work in any binary,
compressed, marked up, nonproprietary or proprietary form, including
any word processing or hypertext form. However, if you provide access
to or distribute copies of a Project Gutenberg-tm work in a format
other than "Plain Vanilla ASCII" or other format used in the official
version posted on the official Project Gutenberg-tm web site
(www.gutenberg.org), you must, at no additional cost, fee or expense
to the user, provide a copy, a means of exporting a copy, or a means
of obtaining a copy upon request, of the work in its original "Plain
Vanilla ASCII" or other form. Any alternate format must include the
full Project Gutenberg-tm License as specified in paragraph 1.E.1.

1.E.7. Do not charge a fee for access to, viewing, displaying,
performing, copying or distributing any Project Gutenberg-tm works
unless you comply with paragraph 1.E.8 or 1.E.9.

1.E.8. You may charge a reasonable fee for copies of or providing
access to or distributing Project Gutenberg-tm electronic works
provided that

* You pay a royalty fee of 20% of the gross profits you derive from
  the use of Project Gutenberg-tm works calculated using the method
  you already use to calculate your applicable taxes. The fee is owed
  to the owner of the Project Gutenberg-tm trademark, but he has
  agreed to donate royalties under this paragraph to the Project
  Gutenberg Literary Archive Foundation. Royalty payments must be paid
  within 60 days following each date on which you prepare (or are
  legally required to prepare) your periodic tax returns. Royalty
  payments should be clearly marked as such and sent to the Project
  Gutenberg Literary Archive Foundation at the address specified in
  Section 4, "Information about donations to the Project Gutenberg
  Literary Archive Foundation."

* You provide a full refund of any money paid by a user who notifies
  you in writing (or by e-mail) within 30 days of receipt that s/he
  does not agree to the terms of the full Project Gutenberg-tm
  License. You must require such a user to return or destroy all
  copies of the works possessed in a physical medium and discontinue
  all use of and all access to other copies of Project Gutenberg-tm
  works.

* You provide, in accordance with paragraph 1.F.3, a full refund of
  any money paid for a work or a replacement copy, if a defect in the
  electronic work is discovered and reported to you within 90 days of
  receipt of the work.

* You comply with all other terms of this agreement for free
  distribution of Project Gutenberg-tm works.

1.E.9. If you wish to charge a fee or distribute a Project
Gutenberg-tm electronic work or group of works on different terms than
are set forth in this agreement, you must obtain permission in writing
from both the Project Gutenberg Literary Archive Foundation and The
Project Gutenberg Trademark LLC, the owner of the Project Gutenberg-tm
trademark. Contact the Foundation as set forth in Section 3 below.

1.F.

1.F.1. Project Gutenberg volunteers and employees expend considerable
effort to identify, do copyright research on, transcribe and proofread
works not protected by U.S. copyright law in creating the Project
Gutenberg-tm collection. Despite these efforts, Project Gutenberg-tm
electronic works, and the medium on which they may be stored, may
contain "Defects," such as, but not limited to, incomplete, inaccurate
or corrupt data, transcription errors, a copyright or other
intellectual property infringement, a defective or damaged disk or
other medium, a computer virus, or computer codes that damage or
cannot be read by your equipment.

1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right
of Replacement or Refund" described in paragraph 1.F.3, the Project
Gutenberg Literary Archive Foundation, the owner of the Project
Gutenberg-tm trademark, and any other party distributing a Project
Gutenberg-tm electronic work under this agreement, disclaim all
liability to you for damages, costs and expenses, including legal
fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT
LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE
PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE
TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE
LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR
INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGE.

1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a
defect in this electronic work within 90 days of receiving it, you can
receive a refund of the money (if any) you paid for it by sending a
written explanation to the person you received the work from. If you
received the work on a physical medium, you must return the medium
with your written explanation. The person or entity that provided you
with the defective work may elect to provide a replacement copy in
lieu of a refund. If you received the work electronically, the person
or entity providing it to you may choose to give you a second
opportunity to receive the work electronically in lieu of a refund. If
the second copy is also defective, you may demand a refund in writing
without further opportunities to fix the problem.

1.F.4. Except for the limited right of replacement or refund set forth
in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO
OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE.

1.F.5. Some states do not allow disclaimers of certain implied
warranties or the exclusion or limitation of certain types of
damages. If any disclaimer or limitation set forth in this agreement
violates the law of the state applicable to this agreement, the
agreement shall be interpreted to make the maximum disclaimer or
limitation permitted by the applicable state law. The invalidity or
unenforceability of any provision of this agreement shall not void the
remaining provisions.

1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the
trademark owner, any agent or employee of the Foundation, anyone
providing copies of Project Gutenberg-tm electronic works in
accordance with this agreement, and any volunteers associated with the
production, promotion and distribution of Project Gutenberg-tm
electronic works, harmless from all liability, costs and expenses,
including legal fees, that arise directly or indirectly from any of
the following which you do or cause to occur: (a) distribution of this
or any Project Gutenberg-tm work, (b) alteration, modification, or
additions or deletions to any Project Gutenberg-tm work, and (c) any
Defect you cause.

Section 2. Information about the Mission of Project Gutenberg-tm

Project Gutenberg-tm is synonymous with the free distribution of
electronic works in formats readable by the widest variety of
computers including obsolete, old, middle-aged and new computers. It
exists because of the efforts of hundreds of volunteers and donations
from people in all walks of life.

Volunteers and financial support to provide volunteers with the
assistance they need are critical to reaching Project Gutenberg-tm's
goals and ensuring that the Project Gutenberg-tm collection will
remain freely available for generations to come. In 2001, the Project
Gutenberg Literary Archive Foundation was created to provide a secure
and permanent future for Project Gutenberg-tm and future
generations. To learn more about the Project Gutenberg Literary
Archive Foundation and how your efforts and donations can help, see
Sections 3 and 4 and the Foundation information page at
www.gutenberg.org



Section 3. Information about the Project Gutenberg Literary Archive Foundation

The Project Gutenberg Literary Archive Foundation is a non profit
501(c)(3) educational corporation organized under the laws of the
state of Mississippi and granted tax exempt status by the Internal
Revenue Service. The Foundation's EIN or federal tax identification
number is 64-6221541. Contributions to the Project Gutenberg Literary
Archive Foundation are tax deductible to the full extent permitted by
U.S. federal laws and your state's laws.

The Foundation's principal office is in Fairbanks, Alaska, with the
mailing address: PO Box 750175, Fairbanks, AK 99775, but its
volunteers and employees are scattered throughout numerous
locations. Its business office is located at 809 North 1500 West, Salt
Lake City, UT 84116, (801) 596-1887. Email contact links and up to
date contact information can be found at the Foundation's web site and
official page at www.gutenberg.org/contact

For additional contact information:

    Dr. Gregory B. Newby
    Chief Executive and Director
    gbnewby@pglaf.org

Section 4. Information about Donations to the Project Gutenberg
Literary Archive Foundation

Project Gutenberg-tm depends upon and cannot survive without wide
spread public support and donations to carry out its mission of
increasing the number of public domain and licensed works that can be
freely distributed in machine readable form accessible by the widest
array of equipment including outdated equipment. Many small donations
($1 to $5,000) are particularly important to maintaining tax exempt
status with the IRS.

The Foundation is committed to complying with the laws regulating
charities and charitable donations in all 50 states of the United
States. Compliance requirements are not uniform and it takes a
considerable effort, much paperwork and many fees to meet and keep up
with these requirements. We do not solicit donations in locations
where we have not received written confirmation of compliance. To SEND
DONATIONS or determine the status of compliance for any particular
state visit www.gutenberg.org/donate

While we cannot and do not solicit contributions from states where we
have not met the solicitation requirements, we know of no prohibition
against accepting unsolicited donations from donors in such states who
approach us with offers to donate.

International donations are gratefully accepted, but we cannot make
any statements concerning tax treatment of donations received from
outside the United States. U.S. laws alone swamp our small staff.

Please check the Project Gutenberg Web pages for current donation
methods and addresses. Donations are accepted in a number of other
ways including checks, online payments and credit card donations. To
donate, please visit: www.gutenberg.org/donate

Section 5. General Information About Project Gutenberg-tm electronic works.

Professor Michael S. Hart was the originator of the Project
Gutenberg-tm concept of a library of electronic works that could be
freely shared with anyone. For forty years, he produced and
distributed Project Gutenberg-tm eBooks with only a loose network of
volunteer support.

Project Gutenberg-tm eBooks are often created from several printed
editions, all of which are confirmed as not protected by copyright in
the U.S. unless a copyright notice is included. Thus, we do not
necessarily keep eBooks in compliance with any particular paper
edition.

Most people start at our Web site which has the main PG search
facility: www.gutenberg.org

This Web site includes information about Project Gutenberg-tm,
including how to make donations to the Project Gutenberg Literary
Archive Foundation, how to help produce our new eBooks, and how to
subscribe to our email newsletter to hear about new eBooks.

