Garnet

Garnet is the name which can be applied to six similar mineral species,
namely almandine, pyrope, spessartine, grossular, andradite and uvarovite.
To further complicate matters, many garnets are actually a combination of
these minerals. Rhodolite garnet for instance, is a combination of almandine
and pyrope, and is sometimes referred to as pyrope-almandine garnet. There
are also many trade names and other commonly used names which only adds to
the confusion, such as Rhodolite, Tsavorite, Hessonite, Malaya, Mozambique,
Mandarin, Ant-hill, Leuco, Hydrogrossular, Demantoid, Melanite, Topazolite,
Thai. Other names such as "cape ruby" are simply misleading and deceptive.
Some garnets also exhibit color change and stars.

Garnet displays the greatest variety of color of any mineral, occurring in
every color except blue. For example, grossularite can be colorless, white,
gray, yellow, yellowish green, various shades of green, brown, pink,
reddish, or black. Andradite garnet can be yellow-green, green, greenish
brown, orangy yellow, brown, grayish black or black. Pyrope is commonly
purplish red, purplish red, orangy red, crimson, or dark red; and almandite
is deep red, brownish red, brownish black or violet-red. Spessartite garnet
can be red, reddish orange, orange, yellow-brown, reddish brown, or blackish
brown. A few garnets exhibit a color-change phenomenon. They are one color
when viewed in natural light and another color when viewed in incandescent
light.

Varieties:
Rhodolite- violet to purplish-red;
Almandite - red, brownish-red, violetish-red or Purple;
Pyrope - red;
Grossularite - green, yellow, brown, white, colourless, light violet, red,
orangey-red;
Varieties: hessonite (orange to brown), transparent, green, grossularite
(tsavorite); Some show a colour change from a mauve-brown to orange-red.
Andradite - green, yellow, black. Green called demantoid (high lustre and
dispersion); Spessartite - yellow to yellow-brown, dark orangey-brown,
reddish-orange, orange; Uvarovite - emerald green, found only in tiny sizes,
usually opaque.

Sources:
Rhodolite - Sri Lanka, North Carolina, Tanzania, Kenya, South Africa,
Brazil.
Almandite - Sri Lanka, India, Brazil, star from Idaho - USA.
Pyrope - Czechoslovakia, South Africa, Zimbabwe - Rhodesia, Brazil, Arizona.
Grossularite - Sri Lanka, Brazil, Tanzania, Kenya, South Africa, Canada.
Andradite - demantoid: Russia, Italy; translucent yellowish or
greenish-brown, Arizona.
Spessartite - Sri Lanka, Burma, Brazil, Madagascar, Tanzania, Kenya.
Uvarovite - Russia, Finland (hardly mined at all).

History - Since earliest times garnets have been carried as amulets against
accidents in travel. Asiatic peoples and even our Southwest Indians used
them as bullets, believing that their rich, glowing colour might cause more
deadly wounds. The Persians have given the garnet a favoured place as a
royal stone, allowing it to bear their sovereign's image. Red garnet was
once used to relieve fever, yellow garnet to cure jaundice. If the powder
failed, the apothecary was accused of using a substitute.

The use of garnets as a gem or gemstone can be traced to prehistoric times.
However, the first industrial use of garnet appears to have been as coated
sandpaper manufactured in the United States by Henry Hudson Barton (founder
of Barton Mines Corp.) in 1878. Its use has grown from that single sample of
garnet coated sandpaper, to world industrial uses of more than 110,000 tons
per year. In 1994, United States production of industrial garnet was valued
at about $14 million, while gem garnet production was valued at only about
$233,000.
Garnets are isostructural, meaning that they share the same crystal
structure. This leads to similar crystal shapes and properties. Garnets
belong to the isometric crystal class, which produces very symmetrical,
cube-based crystals. The most common crystal shape for garnets however is
the rhombic dodecahedron, a twelve sided crystal with diamond-shaped
(rhombic) faces. This basic shape is the trademark of garnets, for no other
crystal shape is so closely associated with a single mineral group like the
rhombic dodecahedron is with garnets. Most garnets are red in color, leading
to the erroneous belief that all garnets are red. In fact a few varieties,
such as grossular, can have a wide range of colors, and uvarovite is always
a bright green. As a mineral specimen, garnets usually have well shaped and
complex crystals and their color and luster can make for a very beautiful
addition to a collection. At times, garnets are accessory minerals to other
valuable and pretty gem minerals such as topaz, beryl, tourmaline,
vesuvianite and diopside making these specimens extra special.

There is a misconception that garnets are only a red gem but in fact they
come in a variety of colors including purple, red, orange, yellow, green,
brown, black, or colorless. The lack of a blue garnet was remedied in 1990's
following the discovery of color-change blue to red/pink material in Bekily,
Madagascar but these stones are very rare. Color-change garnets are by far
the rarest garnets except uvarovite, which does not come in cuttable sizes.
In daylight, their color can be shades of green, beige, brown, gray and
rarely blue, to a reddish or purplish/pink color in incandescent light. By
composition, these garnets are a mix of spessartine and pyrope, as are
Malaya garnets. The color change of these new garnets is often more intense
and more dramatic than the color change of top quality Alexandrite which is
frequently disappointing, but still sells for many thousands of dollars (US)
per carat. It is expected that blue color-change garnets will match
Alexandrite prices or even exceed them as the color change is often better
and these garnets are much rarer.

Six common varieties of garnet are recognized based on their chemical
composition. They are pyrope, almandine or carbuncle, spessartite,
grossularite (varieties of which are hessonite or cinnamon-stone and
tsavorite), uvarovite and andradite. The garnets make up two solid solution
series; 1. pyrope-almandine-spessarite and 2.
uvarovite-grossularite-andradite.

Garnet is the birthstone for January, and has been used since the Bronze
Age.

Pure crystals of garnet are used as gemstones. Garnet sand is a good
abrasive, and a common replacement for silica sand in sand blasting. Pyrope
varieties are used as kimberlite indicator minerals in diamond prospecting.

Garnets are very abundant in the lower crust and mantle and thus play an
important role in geochemical understanding of the Earth.

Zircon

The name "zircon" is believed to have derived from the Arabic words, "zar",
meaning gold, and "gun", meaning color. For many centuries, the brilliance
of zircon has captured the hearts of those who gazed upon this magnificent
gemstone. Zircon's popularity began to grow in the sixth century when
Italian artisans featured the stone in jewelry designs. During the Middle
Ages, zircon was believed to contain curative powers, protecting the wearer
from diseases and banishing insomnia.

Zircon is a minor gem, but a valuable source of zirconium metal and a major
mineral for today's geologists. Zircon always occurs in crystals. Although
the middle may be stretched into long prisms. Most often brown, zircon also
can be blue, green, red, or colorless. Gem zircons are usually turned blue
by heating brown or clear stones.

Zircon has a very high melting point, is fairly hard (Mohs hardness
6.5-7.5), and is resistant to weathering. As a result, zircon grains can
remain unchanged after being eroded from their mother granites, incorporated
into sedimentary rocks, and even metamorphosed. That makes zircons valuable
as mineral fossils.

Varieties - High, medium and low property.

Sources - Sri Lanka, Burma, Cambodia, Thailand.

History - The terms hyacinth or jacinth were often applied to the
reddish-brown zircon. During the Middle Ages, hyacinth was claimed to have
the power of inducing sleep, of promoting riches, honour and wisdom and of
driving away plagues and evil spirits. The pale yellow to colourless stones
from Ceylon (Sri Lanka) were called jargoons.

Zircon has long had a supporting role to more well-known gemstones, often
stepping in as an understudy when they were unavailable. In the middle ages,
zircon was said to aid sleep, bring prosperity, and promote honor and wisdom
in its owner. The name probably comes from the Persian word zargun which
means "gold-colored," although zircon comes in a wide range of different
colors.
Zircon occurs in a wide range of colors but for many years, the most popular
was the colorless variety which looks more like diamond than any other
natural stone due to its brilliance and dispersion.

Today the most popular color is blue zircon. Most blue zircon, which is
considered an alternate birthstone for December, is a pastel blue, but some
exceptional gems have a bright blue color. Zircon is also available in
green, dark red, yellow, brown, and orange.

Zircon is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, and
other countries.

Zircon is one of the heaviest gemstones, which means that it will look
smaller than other varieties of the same weight. Zircon jewelry should be
stored carefully because although zircon is relatively hard, it can abrade
and facets can chip. Dealers often wrap zircons in individual twists of
paper so that they will not knock against each other in a parcel.

The pervasive occurrence of zircon has become more important since the
discovery of radiometric dating. Zircons contain amounts of uranium and
thorium (from 10 ppm up to 1 wt%) and can be dated using modern analytical
techniques. Since zircons have the capability to survive geologic processes
like erosion, transport, even high-grade metamorphism, they are used as
protolith indicators. The oldest minerals found so far are zircons from the
Narryer Gneiss Terrane, Yilgarn Craton, Western Australia, with an age of
4.404 billion years. This age is interpreted to be the age of
crystallization. These zircons are not only the oldest minerals on earth,
they also show another interesting feature. Their oxygen isotopic
composition has been interpreted to indicate that more than 4.4 billion
years ago there was already water on the surface of the Earth. This is a
spectacular interpretation that has been published in top scientific
journals but is currently the subject of debate. It may be that the oxygen
isotopes, and other compositional features (the rare earth elements), record
more recent hydrothermal alteration of the zircons rather than the
composition of the magma at the time of their original crystallization.

The wide variety of colors of zircon, its rarity, and its relatively low
cost make it a popular collector's stone. Collectors enjoy the search for
all possible colors and variations.

Alexandrite

Hidden for millennium deep within the earth's crust, Alexandrite first came
to light in the XIX century. Discovered by an unnamed farmer in the outposts
of the Urals, a single glowing green crystal was found under the roots of a
stunted tree. This crystal was thought to be an emerald queen of the
empire's jewels. Other glowing crystals were discovered in the same region
and hidden in the Empress Ekaterina's jewel vaults. Unknown to her, a lowly
caretaker of the royal vaults sold these glowing crystals at a high price to
a visiting German Prince who had them cut and set into magnificent settings
for his wife, the Princess. The Princess bejeweled herself with her
Alexandrite ring, Alexandrite earrings, natural Alexandrite white gold,
yellow gold, platinum; many an Alexandrite gemstone in glorious settings.

The alexandrite variety displays a color change (alexandrite effect)
dependent upon light, along with strong pleochroism. Alexandrite results
from small scale replacement of aluminium by chromium oxide, which is
responsible for alexandrite's characteristic green to red color change.
Alexandrite from the Ural Mountains in Russia is green by daylight and red
by incandescent light. Other varieties of alexandrite may be yellowish or
pink in daylight and a columbine or raspberry red by incandescent light. The
optimum or "ideal" color change would be fine emerald green to fine purplish
red, but this is exceedingly rare. Because of their rarity and the color
change capability, "ideal" alexandrite gems are some of the most expensive
in the world.

Varieties - Various shades of green and yellow; brownish, reddish.

Sources - Sri Lanka, Tanzania, Russia, Brazil, Zimbabwe - Rhodesia, Burma.

History - Alexandrite received its name because it was discovered on the
birthday of Czar Alexander II of Russia in 1830. Red and green are also the
colors of the Russian Imperial Guard.

Alexandrite was first discovered in 1831 in an emerald mining region of the
Ural Mountains in Russia. The name comes from Tsar Alexander II of Russia,
on whose birthday the gem was discovered in that country. It was named
"alexandrite" in his honor by the mineralogist Adolf Erik Nordenskiöld. It
is an interesting coincidence that the Russian national colors are green and
red, which may have originated from this gem.
The finest alexandrites were found in the Ural Mountains, the largest cut
stones being in the 30 carat (6 g) range, though many fine examples have
been discovered in Sri Lanka (up to 65 cts.), India (Andhra Pradesh),
Brazil, Myanmar, and especially Zimbabwe (small stones usually under 1 carat
(200 mg) but with intense color change). Overall, stones from any locale
over 5 carats (1 g) would be considered extremely rare, especially gems with
fine color change. Alexandrite is both hard and tough, making it very well
suited to wear in jewelry.

Coveted for their beautiful and mysterious optical effects, when you look at
a Cat's Eye Alexandrite you can see a single band of light on its surface.
Technically known as the "Asteric Effect", this intriguing phenomenon is
unique to the world of gemstones. It is caused by minerals reflecting a band
of light back to the eye like a mirror. Cat's Eye Alexandrite makes
particularly stunning signet rings and are a powerful display of a unique
sense of style.

Russia has remained the primary source of alexandrite since gems from the
mines of the Urals became available on the market. When the Russian deposits
were thought to have been exhausted, interest in the unique colour miracle
decreased - especially since alexandrites from other mines hardly ever
displayed the coveted color change - . But the situation changed
dramatically in 1987, when alexandrites were discovered in a place called
Hematita in Minas Gerais, Brazil. The Brazilian alexandrites showed both a
distinctive colour change and good clarity and color. Thus the somewhat
dulled image of the miraculous stone received another boost. The color of
the Brazilian stones is admittedly not as strong a green as that of Russian
alexandrite, but the color change is clearly discernible.

Today Hematita is one of the most important deposits of alexandrite in
economic terms. Occasionally alexandrite with chatoyancy is discovered
there, an effect which has not yet been observed in Russian alexandrite.
Alexandrites are also recovered from sources in Sri Lanka, but the hue of
these stones compares less than favourably with that of the Uralian
alexandrites. They appear green in daylight and a brownish red in artificial
light. The Tunduru area in southern Tanzania has also produced some
outstanding specimens since the mid-1990's. Alexandrites are also found in
India, Burma, Madagascar and Zimbabwe. Although this stone is still
considered a rarity, specialised gemstone dealers do stock it, especially
since improved trade relationships between Russia and the rest of the world
have ensured a better supply of Russian alexandrites to the market.

With its good hardness of 81/2, alexandrite is an uncomplicated stone to
wear. The more distinct the change of colour, the more valuable the stone. A
fine alexandrite should show a vivid bluish-green in daylight and a
purplish-red in artificial light, without any trace of undesirable brown or
grey. If the origin of the stone is known beyond dispute to be Russia, we
are talking about a real rarity of enormous value. Finely faceted
alexandrites above one carat are thus among the most expensive gemstones in
the world, rarer than fine ruby, sapphire or emerald.

Alexandrite is a stone for experts, enthusiasts and connoisseurs, a true
understatement stone. Its uniqueness and high value are not evident at first
sight. The mysterious color change will only occur on exposure to different
light sources. But if you really get involved in alexandrite, you will be
utterly fascinated by this gem. Maybe you will also feel some of the
mysterious magic and lore ascribed to it. It is considered a stone of very
good omen. In critical situations it is supposed to strengthen the wearer's
intuition, and thus help him or her find new ways forward in situations
where logic will not provide an answer. Alexandrite is also reputed to aid
creativity and inspire imagination.

Spinel

Spinel is a very attractive and historically important gemstone mineral. Its
typical red color, although pinker, rivals the color of ruby. In fact, many
rubies, of notable fame belonging to crown jewel collections, were found to
actually be spinels. Perhaps the greatest mistake is the Black Prince's Ruby
set in the British Imperial State Crown. Whether these mistakes were
accidents or clever substitutions of precious rubies for the less valuable
spinels by risk taking jewelers, history is unclear. The misidentification
is meaningless in terms of the value of these gems for even spinel carries a
considerable amount of worth and these stones are priceless based on their
history, let alone their carat weight and pedigree.

Today, expensive rubies are still substituted for by spinel in much the same
way a diamond is substituted by cubic zirconia. Not to commit a fraud or
theft but to prevent one. Spinel may take the place of a ruby that would
have been displayed in public by an owner who is insecure about the rubies
safety. The spinel probably is still valuable but better to lose a $100,000
dollar spinel than a $1 million dollar ruby!

Spinel and ruby are chemically similar. Spinel is magnesium aluminum oxide
and ruby is aluminum oxide. This is probably why the two are similar in a
few properties. Not suprisingly, the red coloring agent in both gems is the
same element, chromium. Spinel and Ruby also have similar luster (refractive
index), density and hardness. Although ruby is considerably harder (9) than
spinel, spinel's hardness (7.5 - 8) still makes it one of the hardest
minerals in nature.

Varieties - Star material is very rare.

History - Two of the stones among the Crown Jewels of England are spinels,
although they were once thought to be rubies. They are the Black Prince's
Ruby and the Timur Ruby. The 361 carat Timur Ruby is the world's most famous
spinel. Spinel was recognized as a separate species as early as 1587 in
Burma.

Spinel is the great imposter of gemstone history: many famous rubies in
crown jewels around the world are actually spinel. The most famous is the
Black Prince's Ruby, a magnificent 170-carat red spinel that currently
adorns the Imperial State Crown in the British Crown Jewels after a long
history: Henry V even wore it on his battle helmet! The Timur Ruby, a
352-carat red spinel now owned by Queen Elizabeth, has the names of some of
the Mughal emperors who previously owned it engraved on its face, an
undeniable pedigree!
In Burma (Myanmar), where some of the most beautiful colors are mined,
spinel was recognized as a separate gem species as early as 1587. In other
countires the masquerade lasted for hundreds of years after that. Spinels
were most often referred to as "balas rubies" which may have referred to
color or to country of origin.

Now treasured for its own sake, spinel is a favorite of gem dealers and gem
collectors due to its brilliance, hardness and wide range of spectacular
colors. In addition to beautiful rich reds, spinel can be found in a range
of beautiful pastel shades of pink and purple. Of particular interest is a
vivid hot pink with a tinge of orange that is mined in Burma that is one of
the most spectacular gemstone colors in any gem species. Spinel also comes
in beautiful blues which are sometimes called cobalt spinel, but these are
very very rare.

Because spinels made in a laboratory are often used for imitation birthstone
rings, many people think "synthetic" when they hear the name "spinel." They
have often never even seen the real thing. In fact, the main thing holding
back greater recognition for spinel is rarity. Fine spinels are now more
rare than the rubies they used to imitate. Strangely, they are also more
affordable: in the gem world, too rare can be a drawback because so few
people even get a chance to grow to love these gem varieties.

In addition to Burma, now known as Myanmar, spinel is mined in Sri Lanka,
Tanzania, and Tadjikstan, part of the former Soviet Union.

Spinel is a durable gemstone that is perfect for all jewelry uses. It is
most often faceted in oval, round, or cushion shapes and is not currently
found in calibrated sizes due to its rarity.

The name "spinel" is derived from the Greek word for spark, in reference to
the fiery red color of spinels often used for gems. The transparent red
spinels are also called spinel-rubies or balas-rubies and were often
confused with actual rubies in ancient times. "Balas" is derived from
Balascia, the ancient name for Badakhshan, a region in central Asia situated
in the upper valley of the Kokcha river, one of the principal tributaries of
the Oxus river. Yellow spinel is called rubicelle and violet-colored
manganese-bearing spinel is called almandine.

Spinel is found as a metamorphic mineral, and also as a primary mineral in
basic rocks, because in such magmas the absence of alkalis prevents the
formation of feldspars and any aluminium oxide present will form corundum or
combine with magnesia to form spinel. This is why spinel and ruby are often
found together.

Sri Lanka produces blue spinels colored by cobalt. Such cobalt blue spinels
are highly sought after by collectors. The best pieces are an intense blue
unique in the world of gems.

Aquamarine Gemstones

Aquamarine is the blue, or perhaps more correctly, blue-green or aqua
variety of the mineral beryl. Other gemstone color varieties that belong to
beryl include emerald, morganite, and heliodor. Other colors of beryl are
simply referred to by their colour, such as red beryl. Most gem aquamarines
have been heat treated to produce the popular blue-green varieties from less
desirable yellow or pale stones.

Its light blue arouses feelings of sympathy, trust, harmony and friendship.
Good feelings. Feelings which are based on mutuality and which prove their
worth in lasting relationships. The blue of aquamarine is a divine, eternal
color, because it is the color of the sky. However, aquamarine blue is also
the colour of water with its life-giving force. And aquamarine really does
seem to have captured the lucid blue of the oceans. No wonder, when you
consider that according to the saga it originated in the treasure chest of
fabulous mermaids, and has, since ancient times, been regarded as the
sailors' lucky stone. Its name is derived from the Latin aqua (water) and
mare (sea). It is said that its strengths are developed to their best
advantage when it is placed in water which is bathed in sunlight. However,
it is surely better still to wear aquamarine, since according to the old
traditions this promises a happy marriage and is said to bring the woman who
wears it joy and wealth into the bargain. An ideal gem, not only for loving
and married couples.

Treatments - Almost all aquamarine is heat-treated to enhance its blue
color. Irradiation with neutron, gamma rays or with x-rays. Colour change is
permanent and is an accepted practice. A morganite (pink beryl) turns deep
purple blue (Maxixe type) upon ultraviolet irradiation, though the color is
not stable.

History - The word aquamarine comes from the Latin for sea water. In 1910 a
243 lb. crystal was found in Brazil. The outside was greenish and the inside
was blue. It sold for $25,000 and was cut into many high quality gems. The
American Museum of Natural History has a 13 lb. uncut piece of the green
outside portion.

Aquamarine (Lat. aqua marina, "water of the sea") is a gemstone-quality
transparent variety of beryl, having a delicate blue or blue-green color,
suggestive of the tint of sea-water. It's closely related to the gem
emerald. Colors vary and yellow beryl, called heliodor; rose pink beryl,
morganite; and white beryl, goshenite are known.
Aquamarine is one of our most popular and best-known gemstones, and
distinguishes itself by many good qualities. It is almost as popular as the
classics: ruby, sapphire and emerald. In fact it is related to the emerald,
both belonging to the beryl family. The color of aquamarine, however, is
usually more even than that of the emerald. Much more often than its famous
green cousin, aquamarine is almost entirely free of inclusions. Aquamarine
has good hardness (7_ to 8 on the Mohs scale) and a wonderful shine.

That hardness makes it very tough and protects it to a large extent from
scratches. Iron is the substance which gives aquamarine its color, a colour
which ranges from an almost indiscernible pale blue to a strong sea-blue.
The more intense the color of an aquamarine, the more value is put on it.
Some aquamarines have a light, greenish shimmer; that too is a typical
feature. However, it is a pure, clear blue that continues to epitomise the
aquamarine, because it brings out so well the immaculate transparency and
magnificent shine of this gemstone.

The bright blue of this noble beryl is making more and more friends. The
various color nuances of aquamarine have melodious names: the rare, intense
blue aquamarines from the Santa Maria de Itabira mine in Brazil, which make
every gemstone lover's heart beat faster, are called 'Santa Maria'. Similar
nuances come from a few gemstone mines in Africa, particularly Mozambique.
To help distinguish them from the Brazilian ones, these aquamarines have
been given the name 'Santa Maria Africana'. The 'Espirito Santo' colour of
aquamarines from the Brazilian state of that name is of a blue that is not
quite so intense. Yet other qualities are embodied in the stones from
Fortaleza and Marambaia. One beautiful aquamarine color was named after the
Brazilian beauty queen of 1954, and has the name 'Martha Rocha'.

It can be seen from the names of aquamarine colors just how important Sri
Lanka and Brazil are among the countries where aquamarine is found. Most of
the raw crystals for the world market come from the gemstone mines of that
large South American country. Every now and then, large aquamarine crystals
of immaculate transparency are also found with a magnificent color, a
combination which is very unusual in gemstones. And very occasionally,
sensationally large aquamarine crystals come to light in Brazil, such as the
crystal of 110.5 Kg found in 1910 in Marambaia/Minas Gerais, or for example
the 'Dom Pedro', weighing 26 Kg and cut in Idar-Oberstein in 1992 by the
gemstone designer Bernd Munsteiner, the largest aquamarine ever to have been
cut. However, aquamarines are also found in other countries, for example
Nigeria, Zambia, Madagascar, Mozambique, Afghanistan and Pakistan.

There is hardly any other gemstone in modern jewellery design which is
refined in such a variety of ways as aquamarine. Whether it is fashioned as
a clear, transparent gem in the classical step cut, or creatively cut in a
more modern design, it is always fascinatingly beautiful. Uncut too, or with
many inclusions which can be brought into play by the designer in the way in
which the stone is cut, it can be refined to produce the most beautiful
creations.

Designers call it their favourite gemstone. Again and again they take the
world by surprise with a new, modern artistic cut, and when they are
breaking new ground, aquamarine is a gem that they particularly like to work
with.

Without doubt, these creative designer cuts have contributed to the great
popularity of this gem. The lucid colour of aquamarine makes it easy to see
inclusions. For this reason, aquamarine should always be of the greatest
possible transparency. On the other hand, particularly charming effects can
sometimes be achieved in the way the gemstone is cut by bringing the
inclusions into play. The light color of aquamarine leaves the gemstone
designer free to bring out the brilliance of the gem with fine grooves,
notches, curves and edges. In this way, each aquamarine becomes a unique
specimen, whose magical attraction no woman can resist.

Quartz Crystals

Quartz is the most common mineral on the face of the Earth. Gem varieties
include amethyst (purple), citrine (yellow), milky quartz (cloudy, white
variety), rock crystal (clear variety), rose quartz (pink to reddish-pink
variety), and smokey quartz (brown to grey variety).

The word amethyst comes from the Greek amethustos meaning "not drunk".
Therefore, it has been considered a charm against intoxication. A legend
accounts for the origin of the stone. Supposedly, Bacchus, the god of wine
and conviviality, grew angry at a slight and swore revenge. He decreed that
the first mortal to come across his path was to be eaten by tigers.
Amethyst, a beautiful maiden on her way to worship at the shrine of Diana,
happened to be the victim. Diana, the huntress, changed Amethyst into
colorless quartz to protect her from the tigers. When Bacchus witnessed the
miracle, he repented and poured wine over the stone, staining it purple. The
wine failed to cover the entire stone evenly, and the feet and part of the
legs remained clear crystal. So, in keeping with the legend, amethyst
crystals are usually uneven in color with a colourless base.

Varieties - A variety of quartz, silicon dioxide, which appears to be dark
purple in transparent light. A transparent variety of quartz, silicon
dioxide, occurring in yellow to red-orange to orange-brown. The name is
derived from citron, which is French for lemon.

Treatments - Poor quality amethyst is often heat-treated to achieve a
desirable citrine colour.

History - The name "quartz" comes from the German "Quarz", which is of
Slavic origin (Czech miners called it krem). Other sources insist the name
is from the Saxon word "Querkluftertz", meaning cross-vein ore.
Quartz is the most common material identified as the mystical substance
maban in Australian Aboriginal mythology.

Roman naturalist Pliny the Elder believed quartz to be permanently frozen
ice. He supported this idea by saying that quartz is found near glaciers in
the Alps and that large quartz crystals were fashioned into spheres to cool
the hands. He also knew of the ability of quartz to split light into a
spectrum.

Nicolas Steno's study of quartz paved the way for modern crystallography. He
discovered that no matter how distorted a quartz crystal, the long prism
faces always made a perfect 60 degree angle.

Charles Sawyer invented the commercial quartz crystal manufacturing process
in Cleveland, OH. This initiated the transition from mined and cut quartz
for electrical appliances to manufactured quartz.

Quartz is one of the most common minerals in the Earth's continental crust.
It has a hexagonal crystal structure made of trigonal crystallized silica
(silicon dioxide, SiO2), with a hardness of 7 on the Mohs scale. Density is
2.65 g/cm³. The typical shape is a six-sided prism that ends in six-sided
pyramids, although these are often twinned, distorted, or so massive that
only part of the shape is apparent from a mined specimen. Additionally a bed
is a common form, particularly for varieties such as amethyst, where the
crystals grow up from a matrix and thus only one termination pyramid is
present. A quartz geode consists of a hollow rock (usually with an
approximately spherical shape) with a core lined with a bed of crystals.
Quartz is one of the world's most common crustal minerals and goes by a
bewildering array of different names. The most important distinction between
types of quartz is that of macrocrystalline (individual crystals visible to
the unaided eye) and the microcrystalline or cryptocrystalline varieties
(aggregates of crystals visible only under high magnification). Chalcedony
is a generic term for cryptocrystalline quartz. The cryptocrystalline
varieties are either translucent or mostly opaque, while the transparent
varieties tend to be macrocrystalline.

Although many of the varietal names historically arose from the color of the
mineral, current scientific naming schemes refer primarily to the
microstructure of the mineral. Colour is a secondary identifier for the
cryptocrystalline minerals, although it is a primary identifier for the
macrocrystalline varieties. This does not always hold true.

Not all varieties of quartz are naturally occurring. Prasiolite, an olive
colored material, is produced by heat treatment; natural prasiolite has also
been obeserved in Lower Silesia in Poland. Although citrine occurs
naturally, the majority is the result of heat-treated amethyst. Carnelian is
widely heat-treated to deepen its color.

Because natural quartz is so often twinned, much quartz used in industry is
synthesized. Large, flawless and untwinned crystals are produced in an
autoclave via the hydrothermal process: emeralds are also synthesized in
this fashion.

Quartz occurs in hydrothermal veins and pegmatites. Well-formed crystals may
reach several metres in length and weigh hundreds of kilograms. These veins
may bear precious metals such as gold or silver, and form the quartz ores
sought in mining. Erosion of pegmatites may reveal expansive pockets of
crystals, known as "cathedrals."

Quartz is a common constituent of granite, sandstone, limestone, and many
other igneous, sedimentary, and metamorphic rocks.

Tridymite and cristobalite are high temperature polymorphs of SiO2 which
occur in high silica volcanic rocks. Lechatelierite is an amorphous silica
glass SiO2 which is formed by lightning strikes in quartz sand.

Quartz is also a type of piezoelectric crystal that creates electricity
through a process called piezoelectricity when mechanical stress is put upon
it. One of the earliest uses for a quartz crystal was a phonograph pickup.
Today, one of the most ubiquitous piezoelectric uses of quartz is as a
crystal oscillator -- in fact these oscillators are often simply called
"quartzes". The same principle is also used for very accurate measurements
of very small mass changes by means of the quartz crystal microbalance.