[Illustration: Faceted, egg-shaped, 7000-carat rock crystal from
Brazil. The gold stand is inset mostly with Montana sapphires. The
gem was cut and the stand was designed and constructed by Capt. John
Sinkankas of California. (7¼ inches high in all.)]
_Gems_
_in the_
SMITHSONIAN
INSTITUTION
by PAUL E. DESAUTELS
_Associate Curator_
Division of Mineralogy
WASHINGTON, D. C.
1965
[Illustration: FOR THE INCREASE AND DIFFVSION OF KNOWLEDGE AMONG
MEN • SMITHSONIAN INSTITVTION • WASHINGTON 1846]
SMITHSONIAN
INSTITUTION
PUBLICATION
No. 4608
LIBRARY OF CONGRESS
Card No. 65-60068
CONTENTS
The National Gem Collection 1
The Study of Gems 3
The Shaping of Gemstones 10
Gem Substitutes 20
Gem Lore 24
The Principal Gem Species 27
Some Notable Gems in the Collection 70
[Illustration: Prof. F. W. Clarke, former honorary curator of the
Division of Mineralogy who assembled the Smithsonian Institution’s
first gem collection in 1884.]
[Illustration: Dr. Isaac Lea, Philadelphia gem collector whose
collection was the nucleus around which the Smithsonian
Institution’s gem collection has been built through the years.]
[Illustration: Dr. Leander T. Chamberlain, son-in-law of Dr. Isaac
Lea, who became honorary curator of the Smithsonian Institution’s
gem collection in 1897. Income from his bequest is used to purchase
gems for the Isaac Lea gem collection.]
1
THE NATIONAL GEM COLLECTION
Man has been using certain mineral species for personal adornment since
prehistoric times. However, of the almost 2000 different mineral
species, relatively few, perhaps only 100, have been used traditionally
as gems. To be used as a gem, a mineral species must have durability as
well as beauty. Lack of durability eliminates most minerals as gems,
although some relatively fragile gem materials such as opal are prized
because of their exceptional beauty. Actually, some gem materials are
not minerals at all. Pearl, amber, jet, and coral are formed by living
organisms.
In the National Gem Collection, the Smithsonian Institution has
assembled a large representation of all known gem materials. The display
portion of the collection consists of more than 1000 items selected to
illustrate the various kinds of gems and to show how their beauty is
enhanced by cutting and polishing. All of these gems are gifts of
public-spirited donors who, by giving the gems directly or by
establishing endowments for their purchase, have contributed to the
enjoyment of the many thousands of persons who visit the Smithsonian
Institution each week.
The National Gem Collection had its beginning in 1884 when Prof. F. W.
Clarke, then honorary curator of the Division of Mineralogy, prepared an
exhibit of American precious stones as a part of the Smithsonian
Institution’s display at the New Orleans Exposition. The same collection
was displayed at the Cincinnati Exposition the following year. Between
1886 and 1890 the growth of the collection was slow, but in 1891 most of
the precious stones collected by Dr. Joseph Leidy of Philadelphia were
obtained, and these, combined with those already on hand, were exhibited
at the World’s Columbian Exposition at Chicago in 1893.
Great stimulus was given the collection in 1894 when Mrs. Frances Lea
Chamberlain bequeathed the precious stones assembled by her father, Dr.
Isaac Lea. Her husband, Dr. Leander T. Chamberlain, who in 1897 became
honorary curator of the collection, contributed a large number of
specimens and, upon his death, left an endowment fund. The income from
that fund has been used to steadily increase the collection over the
years. Extremely rare and costly gems suitable for exhibition are beyond
the income derived from the Chamberlain endowment, but this gap has been
filled by many important donations, the most notable being the gift of
the Hope Diamond by Harry Winston, Inc., New York City. Thus, from
modest beginnings in 1884, there has been accumulated the magnificent
collection of gems belonging to the people of the United States. The
collection is displayed in the Smithsonian Institution’s great Museum of
Natural History.
[Illustration: Left to right: 42-carat brazilianite, 8.4-carat
euclase, 7.6-carat benitoite, 12-carat willemite, 20-carat
amblygonite, and 16-carat orthoclase. (About two-thirds actual
size.)]
2
THE STUDY OF GEMS
To the average person it might seem that a jeweler’s showcase of gems
presents innumerable kinds of precious stones, when actually only a few
species of minerals are there. Perhaps only diamond, ruby, emerald,
aquamarine, sapphire, opal, tourmaline, and amethyst would comprise the
entire stock. Yet, since the mineral kingdom consists of about 2000
distinct species, it would seem that a few more kinds of gemstones would
be available. Certainly, many more minerals than are seen displayed by
the jeweler have been used as gems over the centuries. The study of all
these species of gem minerals constitutes modern gemology—a specialized
branch of the science of mineralogy.
With the few exceptions already noted, all gems are minerals found in
the earth’s crust. A mineral is a natural substance having a definite
chemical composition and definite physical characteristics by which it
can be recognized. However, for a mineral to qualify as a gem it must
have at least some of the accepted requirements—brilliance, beauty,
durability, rarity, and portability. Of course, if a gemstone happens to
be “fashionable” it will have additional importance. Rarely does a
single gem possess all of these qualities. A fine-quality diamond,
having a high degree of brilliance and fire, together with extreme
hardness and great rarity, comes closest to this ideal, and in the world
of fashion the diamond is unchallenged among gems. The opal, by
contrast, is relatively fragile, and it depends mainly on its rarity and
its beautiful play of colors to be considered gem material.
When a gem material, as found in nature, has at least a minimum number
of the necessary qualities, it is then the task of the lapidary, or gem
cutter, to cut it and polish it in such a way as to take greatest
advantage of all its possibilities for beauty and adornment.