Alexandrite
- Another of June's birthstones is the Alexandrite. The stone is named
after Prince Alexander of Russia (which is why the "A" in Alexandrite is
capitalized), who was to later become Czar Alexander II in 1855).
Discovered in 1839 on the day of the prince's birthday, Alexandrite was
found in an emerald mine in the Ural Mountains of Russia. Because it is a
relatively recent discovery, there has been little time for myth and
superstition to build around this unusual stone. In Russia, the stone
was also popular because it reflected the Russian national colors, green
and red, and was believed to bring good luck. The Alexandrite
possesses an enchanting chameleon-like personality. In daylight, it
appears as a beautiful green, sometimes with a bluish cast or with a
brownish tint. However, under artificial lighting, the stone turns
reddish-violet or violet. Alexandrite belongs to the chrysoberyl
family, a mineral called beryllium aluminum oxide in chemistry jargon,
that contains the elements beryllium, aluminum and oxygen. This is a
hard mineral, only surpassed in hardness by diamonds and corundum
(sapphires and rubies). The unusual colors in Alexandrite are attributed
to the presence of chromium in the mineral. Chrysoberyl is found to
crystallize in pegmatites (very coarse-grained igneous rock,
crystallized from magma) rich in beryllium. They are also found in
alluvial deposits, weathered pegmatites containing the gemstones that
are carried by rivers and streams. Alexandrite is an uncommon stone,
and therefore very expensive. Sri Lanka is the main source of
Alexandrite today, and the stones have also been found in Brazil,
Malagasy, Zimbabwe, Tanzania and Burma. Synthetic Alexandrite,
resembling a reddish-hued amethyst with a tinge of green, has been
manufactured but the color change seen from natural to artificial
lighting cannot be reproduced. Such stones have met with only marginal
market success in the United States. Back to Top
Amethyst
- The Ancient Greeks believed that whomever wore this gemstone would be
protected from the intoxicating effects of wine and the name is derived
from the Greek word "amethustos" meaning, "not drunk". Amethyst, the
birthstone for February, is a variety of quartz and occurs in
transparent light to dark purple. It has long been treasured by kings,
queens and religious figures, dating back to the Minoan period (c. 2500
B.C.), because of its rich, royal color. Amethyst was a favorite of
the Art Nouveau craftsmen of the 1920's and is still a favorite of some
of the most creative jewelry designers of today. The most notable
reason for their popularity in jewelry design has been the wide
availability and reasonable price. The two main sources of amethyst are
Brazil and Zambia, although other deposits have been found in Russia,
Sri-Lanka, Mexico, and Arizona.
Enhancements - The
recent scarcity of fine amethyst in recent years has prompted the
production of a manmade synthetic making its way into the market.
Darker hues of amethyst are rarely enhanced to perfect their color,
although some varieties do respond well to heat treatment. Brownish
varieties, when heated, magically turn into the bright yellow or orange
colors known as citrine. This enhancement method is permanent and will
last the lifetime of the gemstone. Back to Top
Aquamarine
- Latin for seawater, this beautiful gemstone inspires visions of the
transparent azure blue waters of the Caribbean. Aquamarine is
identifiable by its flawless crystallization and greenish-blue color,
just like the Caribbean water that is so clear that you can see through
the surface to the sand below. As the birthstone for March, aquamarine
differs greatly from its most famous relative, emerald. Both are from
the gemstone group known as beryl. However, while emeralds are almost
always imperfect (having visible inclusions) aquamarines are almost
always flawless (no visible inclusions under 10power magnification).
Aquamarine has been credited with providing courage, curing laziness and
quickening the intellect. Among some cultures, it had the reputation
for providing happiness and everlasting youth. Brazil is the most
prolific supplier of aquamarine today, with the natural color from this
area leaning towards bluish-green. Other sources of aquamarine include
Tanzania, Kenya, Nigeria, Afghanistan, Russia, and the island of Sri
Lanka.
Enhancements - Aquamarines that you see today are
almost always enhanced by controlled heating. Natural occurring
bluish-green gemstones are heated in this manner to remove the green,
leaving a more pleasing blue hue. The treatment has become a very
common and very acceptable enhancement technique for aquamarine
gemstones, and is one that is permanent for the life of the gemstone. Back to Top
Citrine
- Citrine is the lovely yellowish gem belonging to the quartz species
of gemstones. Its name is derived from its lemon-yellow color and the
French word "citron", meaning lemon. Most commercial citrines are
heat-treated amethysts or smoky quartzes. Citrine is available in
colors ranging from pastel yellows to wonderful orange hues, with the
finest quality citrine being medium to dark in tone, vivid in intensity,
and yellowish-orange in color. It is plentiful in nature and found
principally in Brazil, Bolivia and Spain. The warm hues are reminiscent
of the sun, health and vitality, and represent an incredible value for
those who appreciate its colors. Actually, because of its beauty and
lower price, citrine is commonly used a replacement for topaz as the
birthstone for November.
Enhancements - Citrine is
routinely subjected to heat as a normal part of the processing phase to
improve color. This treatment is very common, it is undetectable and
is very stable. Back to Top
Diamond
- April's birthstone is the diamond. Diamonds are a wonder of nature.
Their cold sparkling fire has held us spell-bound for centuries,
inspiring rich passionate myths of romance, intrigue, power, greed, and
magic. Ancient Hindus, finding diamonds washed out of the ground after
thunderstorms, believed they were created by bolts of lightning. In our
place and time, the diamond is a symbol of enduring love, and often
grace engagement rings. There are many kinds of diamonds: transparent,
translucent or opaque; ranging from colorless to sooty black, with many
colors in between. Mostly transparent diamonds, colorless or tinted, are
used as jewelry. Others are used widely in industry. The color of a
diamond depends on the kind of impurities embedded inside it. Yellow
diamonds, for example, betray minute quantities of nitrogen, while boron
imparts a bluish hue. There are other inclusions in diamonds that have
great scientific value. Such samples are time capsules that yield
valuable information about conditions deep in the Earth's upper mantle
where diamonds formed, and yield clues to the formation and age of the
diamond. Diamonds are the rich cousins of graphite, both crystalline
forms of pure carbon. The enormous differences in their properties is a
result of the way that carbon atoms are bonded together. In graphite,
carbon atoms are arranged in sheets that easily slide past each other,
making them ideal as lubricants and of course, pencil leads. Diamond
crystals, on the other hand, are a tight-fisted network of carbon atoms
securely held in four directions, making it the hardest
naturally-occuring substance in the world. In order to achieve such a
compact and strongly-held network of carbon atoms, it is believed that
diamonds must have crystallized deep under the Earth's surface. At these
depths exist the proper conditions for the formation of diamonds; at 90
to 120 miles deep, pressures are more than 65,000 times that of the
atmosphere at the Earth's surface, with temperatures exceeding 2,700
degrees Fahrenheit. Such pressures and temperatures reproduced in
laboratories have successfully yielded synthetic diamonds. Diamonds are
found in alluvial deposits, that is, gravel swept by streams, rivers,
glaciers and ocean currents. They are also found in sedimentary rock
where gravel deposits and organic material have been compressed into
rock. Diamonds can be found in some samples of kimberlite -- a type of
volcanic rock first identified in Kimberly, South Africa. Diamonds found
in kimberlite are thought to be very old, perhaps as much as three
billion years old. Tiny flecks of diamond have even been found inside
meteorites -- bits of rocky space debris that land on Earth. Diamonds
are crystals, crystals being the ultimate form of symmetry in nature.
The shape of the crystal reflects the internal orderly arrangement of
atoms within it. In diamonds, atoms of carbon are held tightly by
covalent bonding, where two neighboring atoms share an electron,
endowing the diamond crystal with great strength. But despite its
hardness, diamonds can be cut. This is accomplished by cutting the gem
along planes parallel to the faces of the crystal where the tight bonds
between carbon atoms are a little weaker. Found in their natural form,
diamonds can appear quite unimpressive. It is only when they are cut and
polished by skilled craftsmen, such that the light entering it is
reflected and refracted as best possible, only then is their hidden
beauty revealed. Back to Top
Emerald
- The name emerald is derived from the Greek word Smaragdos meaning
"green stone" and, in ancient times, it referred to just about any green
colored gemstone. The birthstone for May, emerald is the most prized
and precious variety of the gemstone group known as beryl, which also
consists of aquamarine and other variations of beryl. Today, most of
the world's Emeralds are mined in Columbia, Brazil and Zambia. The
green color of emerald is incomparable in the world of gemstones and,
for this reason, the color is commonly referred to as "emerald green".
The green color in emerald is caused by the presence of chromium in the
chemical composition of this particular form of beryl. Under
magnification the internal characteristics in an emerald, which include
liquid bubbles, gas bubbles, internal stress fractures, and foreign
crystals form a virtual garden within the gemstone. Most natural
Emeralds contain a variety of these internal inclusions, commonly
referred to as "jarden", which is French for garden. Perfection in
emerald, as in most all things, is the most rare of nature's treasures.
Emerald is the birthstone for May and symbolizes rebirth and youth.
Enhancements
- When mined from the earth, almost all Emeralds have internal
inclusions, or "birthmarks", some of which distinguish them as natural
gemstones. Since early times, merchants would purify the color of
Emeralds by immersing them in oils or paraffin, which would fill the
fissures that were open at the surface and render them almost invisible
to the naked eye. Along with the use of oils and resins, there are much
more sophisticated techniques being used today to clarity enhance
Emeralds. Back to Top
Garnet
- Garnet is a group of gemstones that occur in a virtual rainbow of
colors. The name garnet is derived from the Latin word for grain,
because of the round shape of the crystals, as well as the Greek word
"granatum" for the pomegranate seed. The most common garnets are the
reddish varieties, which bear the names Almandite, Pyrope, and
Rhodolite. These gemstones occur in a range of colors from medium to
dark reddish orange (Almandite and Pyrope) to purplish red to reddish
purple (Rhodolite). Garnet is the traditional birthstone for the month
of January, however, red need not be your color of choice if you were
born in the first month of the year. Other more interesting gems from
the garnet family, being used in jewelry today, consist of pinkish
orange tones (Malaia) to those that exhibit a variety of colors that
have the ability to change tones, depending on the light source, and are
known as color change garnets. Lesser known garnets occur in a
yellowish orange (Spessartite) to the more rare varieties that occur in
green tones (Tsavorite and Demantoid).
Enhancements -
All varieties of garnet are completely natural in color and clarity.
There are no known commercial treatments being done today to enhance
these beautiful gemstones. The owner of any one of garnet's beautiful
colors will cherish the fact that their garnet is one of the few colored
gemstones in today's market that exhibits the exact color and clarity
that mother nature produced, with it's beauty brought to the surface
strictly by the artistry of the cutter. Back to Top
Opal
- The name opal is derived from an Indian word for "stone" and they
are divided into three basic groups with physical properties that vary
considerably:
Precious opal - The special characteristic of these gems is their
opalescence, more appropriately referred to as "play-of-color". The
more predominant types within this group are white opals that are
translucent to semitransparent with play-of-color against a white
bodycolor, black opals that are translucent to opaque with play-of-color
against a black or other dark bodycolor, jelly opals that are
colorless, transparent to semitransparent with little or no
play-of-color, and boulder opals which are opaque and made up of a thin
layer of opal occurring in ironstone matrix; the opal is cut and
polished for the top and the matrix stone is left as a backing that
adds strength and a dark background. Opal always contains water in
variable amounts, but it can be as much as 30%. If not cared for
properly, opals can loose water over time causing crazing, or cracking.
White opals will be the most common found in jewelry and the value
of an opal gemstone will be more determined by its play-of-color than by
size.
Fire opal - These opals are some of the most interesting since
they do not look like what the average consumer would identify as an
opal. They are transparent to semitransparent with or without
play-of-color on a yellow, red or orange bodycolor. The most important
deposits of fire opal are in Mexico and, for that reason, these
beautiful gemstones are often called "Mexican Opals". Common opal - Very common, as the name would imply, and mostly opaque without play-of-color.
Opals, an optional birthstone for the month of October, are relatively
soft gemstones and do not react well to heat or sudden changes in
temperature. Opals are prized by many for their phenomenal play of
color, and while they do make beautiful pieces of jewelry to be worn and
appreciated, extreme care must be taken to protect these gems from
damage. Because of their moisture content they require special care
even when they are not being worn. When purchasing opal jewelry it is
important to discuss their proper care with a gemologist, to insure that
their beauty will be maintained and passed on from generation to
generation. Back to Top
Pearl
- The pearl is unique in the world of gemstones, as it is the only
gemstone that is formed within a living creature. Known as the
birthstone for the month of June, pearls are truly a treasured gift of
the sea and revered for their colors, shapes, sizes and luster. As the
supply of naturally occurring pearls became exhausted man learned how to
cultivated them by implanting an irritant into oysters, which produced
pearls having the same outer appearance as their natural counterpart.
Cultured pearls are grown and harvested in many parts of the world,
including the fresh waters of the Tennessee River, and are available in
many beautiful colors, from the palest crème and white to rose, lilac,
green, gold, gray and the dramatic Tahitian black. The majority,
however, come from Japan, China and the South Pacific. Today, the pearls
from the Japanese Akoyah oysters are becoming the most prized, as
unfavorable biological and environmental conditions have reduced the
availability of larger and finer quality pearls from the salt waters of
Japan. Human innovation, however, has compensated for natures hardships
as man has perfected the cultivation of the larger freshwater oysters
in the lakes of China, producing an abundant crop of beautiful cultured
pearls ranging from lustrous white to naturally occurring soft pastel
colors. To find beautiful pearls in much larger sizes, exceeding nine
and ten millimeters in diameter, one must look to warm waters of the
South Pacific where magnificent whites from Australia and dramatic
natural blacks from Tahiti are harvested to produce one-of-a-kind
necklaces or combined with diamonds for truly magnificent pieces of
jewelry. In the cultivation process of all pearls man can only begin
the process by implanting an irritant within the muscle of the oyster.
After that it is up to the mollusk to produce a fine gem, a very poor
gem, or something in-between. Similar to the way any gemstone is
judged, the value of any pearl will depend on rarity, beauty, size,
color, luster and degree of perfection. In the case of a strand of
pearls, the quality of how well the pearls are matched is also an
important consideration. In the world of pearls there is something for
everyone.
Enhancements - Today, cultured and freshwater
pearls are often bleached to achieve a uniform color. Sometimes they
may be polished in tumblers to achieve better roundness and luster. Back to Top
Peridot
- Peridot has been adored since early times, when the ancient Egyptians
prized it more than 3500 years ago. Some jewelry historians are
convinced that some, if not all, of the emeralds Cleopatra was famous
for wearing were actually peridots mined from what is now known as St.
John's Island in the Red Sea, about 34 miles off the coast of Egypt.
Peridot is a member of the olivine family of gemstones and is the
birthstone for August. This beautiful lime-green gemstone depends
largely on body mass for its concentration of color and, hence, its
beauty. Unfortunately, larger stones have become so rare that the green
hue for which this gem is most praised is seldom seen today. Much of
today's peridot comes from Arizona, however, stones rarely exceed 3
carats in size. Peridot is also found Australia, Brazil, China, Myanmar
(Burma) and Pakistan.
Enhancements - Peridot is
completely natural in color and clarity. There are no known commercial
treatments being done today to enhance these beautiful apple green
gemstones. The owner of a beautiful peridot will cherish the fact that
their peridot is one of the few colored gemstones in today's market
that exhibits the exact color and clarity that mother nature produced,
with it's beauty brought to the surface strictly by the artistry of the
cutter. Back to Top
Ruby
- Ruby, "the King of Gems" and birthstone for July, gets it's name
because of its red color and is derived from the Latin word Rubeus,
meaning red. It was discovered around 1800 that Ruby, as well as
sapphire, belonged to the same mineral group, or species, called
corundum. Prior to that date, both red spinel and garnet were thought
to be, or were referred to, as Ruby. In fact, many of the most
prominent red gemstones in England's Royal Jewels are magnificent red
spinels which, for years, were thought have been rubies. The red color
in Ruby is derived from chromium and historically, the most desirable
ruby color is denoted by the term "pigeons blood". The red color of
Ruby will vary from deposit to deposit and it is, therefore, not
possible to determine the source area of a Ruby based on its color.
Ruby is mined throughout Southeast Asia and while the majority is found
in Thailand and Myanmar (Burma), many exquisite gems also are found in
Sri Lanka and Africa. The designation Burmese-ruby or Siam-ruby are
trade names and refer more to color quality than to actual origin.
Internal characteristics, or inclusions, are very common and while these
inclusions are not necessarily indicative of lower quality, they may
show the difference between natural and synthetic. Certain types of
inclusions may also indicate the source area, or origin, of the
gemstone.
Enhancements - As is the case with many
colored gemstones, Rubies are routinely enhanced to improve their color
and their clarity, the most notable being controlled heating. Many
enhancement procedures are generally recognized and accepted throughout
the jewelry industry and, in most cases, these enhancements are
irreversible, permanent, and will produce a gemstone that is more
beautiful. One should be leery, however, of enhancement techniques that
are not permanent. If you intend to purchase any fine colored gemstone
you should deal with a jeweler who is gemologically trained to explain
the differences. Back to Top
Sapphire
- Birthstone for the month of September, the name Sapphire comes from
the Greek word "Sappheiros", meaning blue. However, sapphires are
formed in nature in a literal rainbow of colors, ranging from very light
to very dark blue, bluish green, yellow, brown, pink, violet, slightly
reddish orange, and a fabulous pinkish-orange that is referred to as
"padparadscha". The name padparadscha is derived from the Sinhalese for
"lotus flower". The mineral name for sapphire is Corundum and its pure
red form it would be known as ruby. The finest sapphire color in the
blue hues is a rich, velvety, cornflower blue known as "Kashmir", which
references the area of India where these precious gemstones were once
mined. Most current production comes from Sri Lanka, Burma, Thailand,
Australia, Africa and Montana. Sapphire will sometimes occur in nature
in such a way whereby numerous needle-like inclusions within the
gemstone are oriented in just the right angles within the stone, to
produce a phenomenon that is called "asterism". As such a six-pointed
star will appear to float just beneath the surface of the gemstone when
subjected to an incandescent light source. These gemstones will always
range from translucent to opaque and they depend on the cutters art to
fashion them into a polished, domed shape known as "cabochon".
Enhancements
- As is the case with many colored gemstones, sapphires are routinely
enhanced to improve their color and their clarity, the most notable
being controlled heating. Many enhancement procedures are generally
recognized and accepted throughout the jewelry industry and, in most
cases, these enhancements are irreversible, permanent, and will produce a
gemstone that is more beautiful. One should be leery, however, of
enhancement techniques that are not permanent. If you intend to
purchase any fine colored gemstone you should deal with a jeweler who is
gemologically trained to explain the differences. Back to Top
Tanzanite
- At its breathtaking best, tanzanite will look amazingly like Kashmir
sapphire, exhibiting the rich, royal velvety blue hue that these
gemstones are prized for, and at a fraction of the price. This exquisite
gemstone is renowned for the wonderful combination of purple and blue
hues, observed in different intensities within the same gemstone.
Tanzanite is a trichroic gemstone, meaning that it gives off three
different colors when view in different directions, or along the optic
axis. The dominant colors being blue and violet will cause tanzanite to
appear violet when exposed to incandescent light and blue when exposed
to fluorescent light. The third less dominant color is reddish brown or
bronze, which is rarely visible to the naked eye. Tanzanite is a form
of zoisite, which was named tanzanite due to its original discovery in
Tanzania in 1967 and, to date, it is not found in any other place in the
world. The introduction and popularity of the gemstone can be
attributed to Tiffany and Company, who exclusively marketed the gemstone
in the late 1960's and early 1970's. The American Gem Society has
designated tanzanite as an option for the traditional December
birthstones blue zircon and turquoise. Tanzanite is one of the most
popular blue gemstones available today and while it has the beauty,
rarity and durability to rival most colored gemstones, your tanzanite
needs slightly more care and attention than due other harder gemstones,
such as sapphire.
Enhancements - As mentioned above,
tanzanite is part of the zoisite mineral species. In its natural from,
tanzanite occurs as a brownish gemstone that is altered by heat to bring
out its inherent rich blue and violet colors. Back to Top
Topaz
- The name topaz was probably derived from the ancient island of
Topazios in the Red Sea. In ancient times all yellow, brown, and
sometimes green gemstones were called "topaz". Even through modern
times, the brownish gemstone commonly referred to as Smokey Topaz is not
topaz at all. Thanks to the adoption of Federal Trade laws, which have
been successful in eliminating most of the misrepresentation of colored
gemstones, the proper gem variety name, Smokey Quartz, is now used to
describe these gems. The quartz variety citrine and yellow
heat-treated amethyst have at times been falsely called "golden topaz"
in the jewelry trade, which lead to real topaz being referred to as
"precious topaz". Commonly, one of the orangey or golden colors of
topaz is worn as the traditional birthstone for November. Topaz,
however, can be found in a rich rainbow of colors with the most valuable
being "Imperial" topaz and pink topaz. Imperial topaz derived its name
after the Russian Czars of the 1800's, and has a magnificent orange
body color, with pinkish-red undertones. In addition to these two,
topaz can be found naturally in yellow, reddish-brown, light blue,
pinky-red, pale green and colorless. Due the abundance of blue topaz,
along with its captivating beauty and low price, it has become an ideal
replacement option for aquamarine as the birthstone for March.
Enhancements
- Most topaz is commonly subjected to enhancement by heat and/or
radiation as a normal part of the fashioning process to improve its
color. Irradiation is used sometimes to change colorless topaz to a
brown or brownish green as a first step in producing treated blue topaz.
The prevalence is common, is very stable and is virtually
undetectable. Back to Top
Tourmaline
- Tourmaline, like garnet and sapphire, occurs in almost every color of
the rainbow from soft pastel tones to bold and brilliant colors that
excite the senses. The people of ancient Ceylon referred to these
beautiful gems as "turmali", the Sinhalese word for many colors.
Varying vibrant hues within the tourmaline group are such that they
command a name that separates them from the more common hues. The vivid
reds and hot pinks are known as Rubellite, vibrant greens that
crystallized containing the chemical chromium and are called Chrome
Tourmaline, and the violetish to greenish blues are referred to as
Indicolite. The pink variety is often used as the birthstone for
October. Not only does tourmaline occur in such a spectacular range of
color, some of these colors occur in a single gemstone and are called
"bi-color" or "parti-colored" tourmalines. In fact, one color
combination known as "watermelon" tourmaline, occurs with a pink center
and green perimeter. Tourmaline is mined in many areas of the world
including Brazil, Afghanistan, East Africa and the United States.
Enhancements
- Color enhancement of tourmalines is very common. Dark blue, blue
green, and green tourmalines are often heated and/or irradiated to
improve their color. Heat and irradiation color enhancement of
tourmaline is permanent. Back to Top
Turqouise
- December's primary birthstone. Turquoise is considered by some to be a
symbol of good fortune and success, believed to bring prosperity to its
wearer. It's name is believed to originate from the French phrase
"pierre turquoise" meaning "Turkish stone" because turquoise was brought
to Europe by Venetian merchants who first acquired it in Turkish
bazaars. It is also considered by some as a love charm. When received as
a gift, the turquoise symbolizes a pledge of affection. Shakespeare
used this lore in "The Merchant of Venice". In it, Leah gave a turquoise
ring to Shylock when he was a bachelor, hoping it would win his
affections so he would ask her to marry him. In Russia, the turquoise is
popularly used in wedding rings. In the language of chemists and
geologists, turquoise is known as "copper aluminum phosphate". Turquoise
is often found in weathered igneous rock that contains copper minerals,
where it crystallizes in veins and nodules. The gemstone usually
develops in rock near water tables, located in semiarid and arid
environments. The chemicals in turquoise come from adjacent rock,
leached out by rain and groundwater. Turquoise is a relatively soft
gemstone, and can be easily scratched and broken. This porous opaque
stone is easily discolored by oil and pigments, and changes color when
it loses some of its water content. A sky blue shade in turquoise is due
to the presence of copper, while iron gives it a greener tone. Ochre
and brown-black veins in the stone occur during the formation of
turquoise, caused by inclusions from nearby rock fragments or from oxide
staining. The most valued variety of turquoise is an intense sky blue
color, like the color of a robin's egg. Hard, relatively non-porous
compact stones have the best appearance because the stone can be finely
polished.
Enhancements - Pale and chalky varieties are
sometimes impregnated with oil, paraffin, liquid plastic and glycerin to
give it a good polish. Back to Top
Zircon
- The alternate birthstone for December is the zircon. Its name is
probably derived from the Arabic words "zar" and "gun", meaning "gold"
and "color". The gemstone is found in a wide range of colors, and
possess great brilliance, fire and clarity. Zircon, in its unchanged
natural form appears colorless to pale yellow, or green. These colors
are caused by minute quantities of thorium and uranium that replaces
zircon in the crystal structure. But over the vast spans of geologic
time, other forces work within the zirconium silicate crystals. The
uranium and thorium inclusions emit radiation that alters the original
crystal structure. A glass-like material is formed, with colors of red
to brown, orange and yellow. The mineral zircon, known as zirconium
silicate, is commonly found as a minor constituent in igneous rock such
as granites and some kinds of metamorphic rock. Gem quality zircon
stones are usually rare. These gemstones are formed mainly in pegmatites
(coarse-grained igneous rock) and in fissures. But due to weathering of
the gem-bearing rocks, most zircons are found in alluvial and beach
deposits. A new blue color for zircon, called "starlight blue," was
created by heating golden brown or yellow zircon in the 1920s. The most
prized zircon is the red gemstone, which is rare. The pure intense blue
and sky blue varieties are also highly valued, while the colorless,
orange, brown and yellow stones are less expensive. Many zircons on the
market are heat treated, and sold as blue, golden brown or colorless
stones. Colorless zircons are the best imitators of diamonds, in
appearance only, with a brilliant fire that is almost as dazzling as the
real thing. However, the resemblance is superficial. Zircon is a
brittle stone, easily broken with a well-placed knock, due to internal
stresses in the crystal caused by radiation damage and heat treatment.
But despite its frail disposition, the stone is still highly valued
because of its stunning beauty. Back to Top
Synthetics and Gemstone Enhancements
Synthetics
- Before purchasing any fine colored gemstone there are things you
should know besides just the weight, the beauty, and the price that you
are going to pay. So that you do not make a costly mistake, it will be
worth your while to work with an AGS Certified Gemologist to help you
make your decision. If a colored gemstone is desirable and has
significant value, you can be sure that there is a synthetic counterpart
to that gemstone available in the marketplace. Synthetic does not mean
just a look-alike gemstone, although there are those as well.
Synthetic means that the laboratory-grown gem is a chemical and
crystalline duplicate of the natural gemstone, and usually it takes a
gemologist, with the aide of special gemological equipment to determine
the difference. Synthetics have natural looking inclusions, which
resemble those found in their natural counterpart.
Enhancements
- Over many centuries man has experimented with, and perfected,
countless methods to improve upon the natural properties of gemstones.
These techniques are known as "enhancements". These methods reflect
upon man's desire to draw upon the truest and purest color and
brilliance that a gemstone has to offer. The art of cutting a gemstone
is man's most basic enhancement method necessary to fully display the
beauty of a fine gem. However, there are many fascinating methods by
which man has demonstrated his ability to draw maximum color, luster,
clarity, and brilliance from nature's most precious gifts. There are
many recognized and accepted enhancement techniques and there are many
that are not. A basic understanding of these enhancement techniques
will add to your appreciation of the beauty, durability and value of the
colored gemstone you already own, or are planning to purchase now or in
the future. Back to Top
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