rubies, emeralds and sapphires share at least four
characteristics which class them as "precious"
gemstones: transparency, hardness, rarity and beauty. Other
gemstones, then, fall into the semi-precious or ornamental class
of gemstone. Because the term "semi-precious" was
determined to be at variance with the international gemstone
standards for terminology, semi-precious stones are now referred
to as ornamental. As far as I know, no one has yet argued with
the term "gemstone."
Quartz is the most widespread mineral on Earth. When colorless,
it is known as rock crystal and, from ancient times into the
eighteenth century, it was believed to be water that had turned
to stone by severe cold. The ancient Greeks learned they could
create fire by focusing the sun's rays through rock crystal, and
the idea that "petrified water" could create fire was
one of the greatest mysteries for ancient philosophers. Priests
were given sole charge of its "sacred" fire; magical
properties surrounded it, and the crystal ball became a favored
device of soothsayers. Almost five thousand years ago, Egyptians
invented glass by perfecting a technique for melting quartz.
Amethyst is one of
the colored quartz gemstones. From ancient times, it has been
claimed to have mystical properties and superstition has
surrounded it. Because of the legend of Bacchus, the god of wine,
bishops wore amethyst on their fingers as a symbol of temperance.
Bacchus is supposed to have fallen in love with Amethyst, one of
Diana's nymphs, and to protect her from his advances, Diana
transformed her into a pure, and inaccessible, rock crystal.
Brokenhearted, Bacchus poured his goblet of wine over the stone
which immediately turned purple.
Because of its pale blue color, Aquamarine is associated with
water and, it is claimed, mermaids leave it on shore. It
symbolizes good luck and happiness and is often carried by those
going on ocean voyages.
Traditionally, the most beautiful turquoise has come from the
orient and, according to legend, has protected those who wore it
against curses, evil spirits and falling. In Pre-Colombian
America, turquoise was so sacred, only the Aztec emperor was
allowed to wear it.
The ancient Egyptians used lapis to decorate their royal tombs
and, it is believed, they invented enamel in an effort to copy
it. Introduced into Europe in the fifth century, it was used to
produce the ultramarine blue pigment in paint.
Four thousand years before Christ, Egyptian women used powdered
malachite and red ochre as a cosmetic to enhance their eyes.
During the middle ages, malachite was claimed to have medicinal
properties and was used, among other things, to treat colic.
Wearing it was supposed to ward off lightening strikes and to aid
sleep by preventing nightmares.
The patterns formed in agate, likened to shrubs, led ancient
alchemists to believe it would help woodcutters to fell trees.
Peasants, believing it would assure them of a good harvest, tied
agate to their waists, and Persians used it to ward off storms
and lightning. And, while it was used to treat the effects of
snakebite, it was also used to inflame the feelings of love.
Garnet was worn by
the Crusaders and given a place of honor in the Court of King
Clovis of France. Believed by alchemists to have curative powers,
garnet was used in the treatment of depression, then called
melancholia, and because of its blood-red color, thought it able
to stop bleeding and ease the complications of child-birth.
While gemstones may
be found just about anywhere, significant numbers of stones are
generally found in specific types of rock formations and
are found in kimberlite pipes, vertical, pipe-like cavities
formed in volcanic rocks low in silica and high in
Aquamarine, amazonite, chrysoberyl,
smoky quartz, topaz and tourmaline are found in pegmatites. Found
within coarse grained rocks, pegmatites are fissures, veins and
geodes having the same composition as the gemstones forming
Alexanderite, garnet, lapis lazuli, ruby and sodalite may be
found in metamorphic rock formations, those rocks formed when the
earth's crust shifted causing an increase in pressure and
temperature. For the last six thousand years, the only place
lapis has been mined is from the deposit at Sar-e-Sang,
and sapphire may be found in volcanic rocks. Also found in
volcanic deposits, agate, amethyst, chalcedony, jasper, opal and
rock crystal may form in cavities created in the molten lava by
amethyst, rhodochrosite and rock crystal may also form in the
hydrothermal veins which allow liquid
and gas to escape from below the earth's surface. Huge deposits
of amethyst have been found in Brazil and Uruguay.
Opals may be found in fissures in sandstone and limestone. These
rocks, called sedimentary rocks, were created from sediment
deposited by water.
Chrysocolla, malachite and turquoise are found where copper
minerals have become exposed to the air. In what is called the
oxidation zone, these minerals are transformed by exposure to
diamonds, garnets, rubies, sapphires, spinels, topazes and
zircons may be deposited in streams. When the rocks that hold
them weather away, the gemstones are released and washed away by
the rains into rivers and streams. If they then collect in one
area in the streambeds, these are called alluvial
first discovered in the United States in the Unakas mountains of
North Carolina. It can be found as pebbles and cobbles from
glacial drift in the beach rock on the shores of Lake Superior.
It is the state stone of Virginia, where it is found in the river
valleys having been washed down from the Blue Ridge Mountains.
Unakite is not limited to the United States.
Malachite is a carbonate found around copper deposits that was
formed by the oxidation of copper minerals. Good stones are a
deep, rich green with noticeable stripes of lighter green. A
comparatively soft stone, it may be dulled or damaged by rough
an opaque deep rich blue and is formed mainly of calcite colored
by blue minerals. This stone may show metallic specks appearing
white or gold in color. As only the most expensive lapis is
without noticeable inclusions, natural lapis may be dyed a
uniform deep blue color as an alternative.
Generally formed as crystals within geodes, fissures or cavities
within other rocks, garnets may be any of several minerals having
similar characteristics. Colors range from colorless, white,
pink, yellow, brown, red, green and black. They can be
transparent or translucent. Most often used are the deep red
Pyrope garnet or the red to reddish brown Almandite garnet.
Found most often near copper deposits, turquoise does not
generally develop in crystal form but in mass. It is an opaque
blue, blue-green or green and often has black veins known as
turquoise matrix running through it. This stone is extremely
sensitive to oils of any kind. Lotions or skin creams may change
its color from blue to an ugly green.
The Quartz family of
compose the majority of all ornamental gemstones. They are formed
in either distinct crystals or in lumps, masses or pebbles.
Colors range from colorless through white, pink, blue, green,
yellow, brown, violet and black. They can be either transparent
Amethyst is a transparent quartz
crystal and a deep rich purple.
Because of its inclusions, Cape amethyst is translucent and a
softer shade of lavender.
Rose quartz is formed in mass, is also
translucent and a delicate shade of pink.
Red quartz is opaque, probably dyed, a
beautiful bright, true red.
The Chalcedony family
stones are considered part of the quartz family because they are
composed of microscopic quartz crystals. Translucent to opaque,
the colors range from white, gray, blue, green, brown, red,
yellow and black.
Carnelian is a translucent chalcedony
in colors of red to a coppery reddish brown.
Containing flakes of mica, aventurine
is a soft green chalcedony with a metallic shimmer.
Tiger-eye is a brown or red-brown
chalcedony containing fibers of silica which give the stone a
Opaque chalcedony is known as jasper and is found in red, brown
incorporated into the stones produce individual and beautiful
patterns. Leopard skin jasper is a
particularly colorful and beautiful light brown stone with
patterns in red, brown and black.
Another in the quartz family, agate can be either translucent or
opaque. It is commonly found in white, gray, blue, green, red,
brown, yellow and black. Mineral inclusions form beautiful and
varied patterns. Blue lace agate is a
light blue stone with stripes in white and darker blue.
Also in the quartz family, onyx is generally black, banded black
and white or black with white inclusions. Black onyx, not shown
here, is opaque and pure black with no inclusions. The colored
onyx shown here was artificially
enhanced to become translucent and a beautiful deep blue and a
sharp, clear green.
Unakite is an altered granite composed of various shades of pink
orthoclase feldspar, green epidote, and generally clear quartz
and is usually mottled in appearance. In good quality, unakite is
considered a semi-precious stone.
Rhodonite is typically pink to red or orange and even black. It's a
beautiful pink color that often has black manganese oxide veins
running through it, giving it a distinct appearance.