|EARLY USES OF GEMS
Gem materials were probably first used as much for their durability as their beauty. But beauty was not ignored. For example, the Stone Age obsidian axe below has been wrought to be attractive as well as practical, and ancient civilizations did fashion gems purely for adornment. Although most were primitive in design, some were highly intricate, with painted surfaces. Down the ages, gems have also been offered as prestigious gifts, and their portability and intrinsic value gave them a natural use as currency.
HOW ARE GEMSTONES FORMED
Most gemstones are mineral crystals that formed during one of three rock making processes: igneous rocks, metamorphic rocks and sedimentary rocks. Gemstones that have a mineral origin are found in rocks, or in gem gravels derived from these rocks. Rocks themselves are made up of one or more minerals, and may be divided into three main types.
The formation of these three types igneous, sedimentary, or metamorphic - is a continuous process, best described in terms of the rock cycle. Gem-quality minerals with in these rocks may be easily accessible at the Earth's surface, or lie buried deep beneath it. Others, separated from their host rock by erosion, are carried by rivers to lakes or the sea.
Most minerals contain visible traces of their genesis - perhaps tiny crystals of other minerals that were caught up in the growth of the larger host crystal, or formed simultaneously as it grew, internal fractures that have been partially healed during growth, or traces of earlier growth stages, marked by zoning. Gemologists use the word inclusions to describe these and other internal phenomena. Inclusions in a gemstone, viewed through a microscope or a 10x loupe, can give information about the geological environment in which the mineral was formed. Inclusions can sometimes identify gemstones and they can prove whether the stone is natural or synthetic. Inclusions can also tell us where a gemstone comes from.
OPTICAL PROPERTIES : COLOR IS THE MOST OBVIOUS visual feature of a gem, but in fact it is just one of many optical properties, all of which are dependent upon light. The individual crystalline structure of a gemstone, interacts with light in a unique way, and determines the optical properties of each gem species. Effects produced by light passing through a gem are described here; those produced by the reflection of light. read more on Refractive index, pleochroic gems, birefringence, fluorescence, lustre, Interference, Allochromatic gems and idiochromatic gems.
World's Largest Diamonds
THE PHYSICAL PROPERTIES of gemstones, their hardness, their specific gravity or density and they way they break, depend on chemical bonding and the atomic structure within the stone. For example, diamond is the hardest natural material known, and graphite is one of the softest, yet both are made of the same element, carbon. It is the way in which the carbon atoms are bonded together in diamond that gives it a greater hardness and resilience. Read more on hardness, tenacity & toughness, thermal and electrical conductivity, magnetism, specific gravity, cleavage and fracture, and crystal systems of gemstones.
The most usual method of fashioning a gem is to cut the surface into a number of flat faces, known as facets. This gives the stone its final shape, or "cut". The craftsman, or lapidary, who cuts the stone aims to show its best features, taking into account its colour, clarity, and weight. He may, however, have to compromise to retain weight and therefore value. There are several stages in the cutting of a gemstone, each of which may be carried out by a different expert. In our example, a rough diamond crystal is fashioned into a brilliant-cut. This is the most popular cut for this stone because it maximizes the gem's naturally strong light dispersion. However because each stone is a different shape, or has imperfections within it, or because retaining the weight is of paramount importance, the cut in its ideal form (the "make") may not be possible.
The shine given to the surface of a stone -either by rubbing it with grit or powder, or against another stone - is its polish. Dark-coloured gemstones and those that are translucent or opaque, for instance opal and turquoise, are often polished rather than faceted, as are organic gems. They may be polished as beads or as flat pieces to be used in inlay work, or cut en cabochon with a smooth, rounded surface and usually a highly polished domed top and flat base. The polishing of stones, is accomplished by the use of very finely powdered abrasives such as corundum powder, tripoli, pumice, putty powder, etc. Each gem material requires special treatment to obtain the best results. The polishing powder should not be quite as hard as the material to be polished, else it may grind rather than polish. The material is used with water or oil to give it a creamy consistency. It is backed by laps of different materials for different purposes. Thus, when backed by a fairly hard metal even tripoli, although much softer, will polish sapphire. On a lap of wood, tripoli would fail to polish hard materials, but would polish amethyst or other quartz gem. A change of speed of the lap, too, changes the effect of the polishing material. The polishing material has to be of a uniform size, preferably water floated or oil floated, to give good results.
CARVING AND ENGRAVING
Carving usually refers to the cutting of decorative objects from a larger mass. Stones as hard as 7 on the Mohs' scale were carved in Ancient Egypt, Babylonia, and China. Impure corundum (emery) was used for carving and engraving in India; nowadays a hand-held chisel or turning machine is used. Popular stones for carving include serpentine, Blue John, malachite, azurite, rhodonite, and rhodochrosite.
Gold is a highly sought-after precious metal that for many centuries has been used as money, a store of value and in jewelry. The metal occurs as nuggets or grains in rocks and in alluvial deposits and is one of the coinage metals. It is a soft, shiny, yellow, dense, malleable, and ductile (trivalent and univalent) transition metal. The colour of gold depends upon the amount and type of impurities it contains. Native gold is typically golden yellow, but in order to vary its colour and increase its hardness for use in jewelry, gold may be alloyed to other metals. Silver, platinum, nickel, or zinc contd...
Silver usually occurs in massive form as nuggets or grains, although it may also be found in wiry, dendritic (tree-like) aggregates. Silver is a very ductile and malleable (slightly harder than gold) univalent coinage metal with a brilliant white metallic luster that can take a high degree of polish. It has the highest electrical conductivity of all metals, even higher than copper, but its greater cost and tarnishability has prevented it from being widely used in place of copper for electrical purposes. On exposure to oxygen in the air a black layer of silver oxide readily forms, tarnishing the surface. Because of this, and the fact that it is contd....
Platinum has been used for thousands of years, but it was not recognised as a chemical element until1735. Of three perecious metals, gold, silver & platinum - it is the rarest and most valuable.Platinum is a slightly more dense than pure gold and about twice as dense as silver. early jewelers had difficulty acheiving the 1,773�C (3,223�F) needed to melt platinum. It wasn't untill the 1920s that the technology was developed sufficiently to work this metal. During the latter eighteenth century, platinum had some industrial uses. It was used to make durable laboratory instruments in Berlin in 1784. In France crucibles for glass production used it, a significant use still today. Platinum also began to impress jewellers and goldsmiths. Leading metal workers, such as Marc Janety, contd...
....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.
World's largest diamonds
gems are formed
The four organic gem groups listed below
are highly prized for their beauty and rarity. However,
they are not as durable as gems from minerals:
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.
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
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.
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.
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
Organic 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
Synthetic gems are made in
laboratories or factories, not in rocks. They have
virtually the same chemical composition and crystal
structure as natural gemstones, so their optical and
physical properties are very similar. However, they can
usually be identified by the differences in their
inclusions. Many gems have been synthesized in the
laboratory, but only a few are produced commercially-
generally for industrial and scientific purposes.
Imitation gems have the appearance of their original
counterparts, but their physical properties are different. They are made to
deceive. Man-made materials, such as glass and synthetic spinel, have been
used to imitate many different gems, but natural stones can also be modified
to resemble more valuable gem. It is possible to enhance authentic
gemstone by hiding cracks and flaws, or by heat-treating or irradiating to
improve their color. Imitation gems merely imitate the color or look of
a natural stone. They can be made out of anything. A cubic zirconia is an
IMITATION diamond, for example. A blue piece of glass could be an imitation
sapphire. A variety of blue synthetic forsterite is an excellent imitation
for tanzanite, while chemically, it's composition is much closer to the
yellowish green peridot. Another classic example is the "alexandrite" set in
many jewelry pieces is actually a variety of vanadium colored synthetic
Gem stones are
scientifically fascinating, too. Gemologists
make a complete study of each
both as it is found in rocks and after it has
That is why the species entries in this website
show the gem in its rough state,
perhaps still embedded in the host rock (or
"matrix"), as well as after it has been cut,
carved. Many entries also feature a
micro-photograph which reveals the internal
structure of the stone by magnifying it many
times. In this world within a world the
gemologist may turn detective, being able to
distinguish between two outwardly similar
gemstones, or between a natural gemstone and a
The word "amethyst" is of Greek origin and is translated as- "amethystus"
meaning not drunken, or intoxicated ("-methystos" from "methyein" or
intoxicated, "methy" = wine).
Aquamarine derives its' name from "sea water." According to some legends,
aquamarine is the treasure of mermaids, with the power to keep sailors safe.
Comes from the Greek word, "adamus" which means unconquerable, utterly
unyielding in attitude or opinion in spite of all appeals, urgings etc.
The name emerald is a derivative of an ancient Persian word, coming to us
through the corruption of the Latin `Smaragdus'. The history of the emerald is
as fascinating as it is voluminous. The ancients prized it as the symbol of
love, rebirth and eternal youth.
Garnet derived its name from the French word ''grenat"
meaning Pomegranate and "granatus" meaning grain. So called from its resemblance
in color and shape to the grains or seeds of the pomegranate.
Greek word "opállios" meaning gem and a source
akin to Sanskrit "upala" precious stone.
The name Peridot comes from the Arabic word "faridat," meaning gem. Ancient
Egyptians called them the "gem of the sun," because of their dazzling brilliance
when seen in the desert sun.
The word Ruby comes from the Latin "ruber," meaning red..It has been said that
the Ruby's red glow comes from an internal flame that cannot be extinguished
Sapphire was named after the Greek word "sapphirus", meaning blue. The striking
deep blue of a quality sapphire is reminiscent of a cloudless night sky.
The name topaz was derived from the Island of Topazos in the Red Sea, which
probably refers to Zeberged, ancient source for peridot. But it is more likely
that the name derives from the Sanskrit word "tapas" meaning fire.
Turquoise was so named because it was initially brought to Europe by way of
Turkey, this stone is one of the first gems to be used in jewelry.
Turquoise was considered by ancients to be a sacred stone, protective against
all manners of evil and ill health. This beautiful gemstone is mined in
Iran and the southwestern United States. A gift of Turquoise represents
friendship and luck. The Persian word for turquoise is "ferozah" or "firozah",
which means victorious.
Crystals, minerals and metals have played various roles in the myths and legends of human cultures throughout history. They are fascinating examples of the attempts of the men and women of ancient times to explain their world without the benefit of science and with each culture's biases, superstitions and interests impressed upon them and therefore provide us with an especially vivid picture of the psychology of ancient man. What gemstone could make heroes stronger? Legends of Jewels, Quartz Mythology, Myths about crystals and myths about jewelry; Some of those ancient myths and legends have come down intact through the centuries. Others have evolved and mutated as result of the input of other culture as they came into contact with one another. We have done our best to dig up the mythology of crystals, minerals rocks and semi-precious stones from ancient stories and organize them by their associated mineral, gemstone, crystal or metal. From the holy silver elephant of Buddhist and Vedic Astrology and other silver myths to the legends, myths and folklore of the Middle East. Follow the links to the left to the ancient and modern myths. Read more on Myths and legends of variuos gemstones.
Early civilization as far back as the
Assyrians (1400 BC) invested rare and beautiful
gemstones with magical properties. Some minerals were
thought to contain a force or possess certain values and
powers. For instance, amethyst was said to prevent
intoxication. Tradition associates a gem with each sign
of the zodiac based on a color system. Color was thought
to unleash the power attributed to the birthstone. In
time, birthstones became associated with calendar months
rather than the zodiac. And people began to select
birthstones in colors other than the original.
Read more about gemstones at Gemological Institute of America, GIA, is the world's foremost authority in gemology, diamond grading, jewelry education, gemology research.
Optical Properties - Physical Properties- Specific Gravity- Lustre- Source- Refraction- Polishing- Inclusions-
Imitation- Formation- Finishing- Faceting- Cuts- Crystal Systems- Conductivity- Chemical Process-
Carving & Engraving- Specific Gravity- Gold- Silver- Platinum- Agate- Coral- Bloodstone- Moonstone- Spinel-
Quartz- Pearl- Jade- Amber- Aquamarine- Diamonds- Garnet- Amethyst- Sapphire- Ruby- Turquoise- Topaz-
Peridot- Emerald- Cubic Zirconia- Opal- January Birthstone- February Birthstone- March Birthstone-
April Birthstone- May Birthstone- June Birthstone- July Birthstone- August Birthstone- September Birthstone-
October Birthstone- November Birthstone- December Birthstone- Aquamarine myths- Garnet myths-
Amethyst myths- Peridot myths- Ruby myths- Sapphire myths- Emerald myths- Topaz myths- Diamond myths-
Turquoise myths- Opal myths- Pearl myths- Aires- Aquarius- Pisces- Capricorn- Saggitarius- Cancer- Scorpio-
Virgo- Libra- Leo- Gemini- Taurus- Largest Diamonds pg1- Largest Diamonds pg2- Largest Daimonds pg3- Largest Diamonds pg4-
Largest Diamonds pg5- Largest Diamonds pg6
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