A silicate of zirconium, this mineral occurs in different colours or may be colourless, the latter often being referred to as the poor man's diamond. In fact, zircon tends to be rather dim and is only used for inexpensive jewelry.
A variety of corundum, like ruby and sapphire, which could be considered a precious stone as it is, in reality, an orange sapphire. It is virtually unknown to the vast majority of people and can therefore be purchased at a reasonable price. However, jewelers are beginning to promote it more and more, and this is a sure sign that the current favorable situation will not remain stable for much longer.
Unakite, often referred as an epidotized granite, consists of a salmon-pink feldspar, green epidote, and quartz. The stone is an opaque coral and olive-green. Sometimes, other shades of green is also seen.
This stone is becoming increasingly rare and costly because the finest material comes from Iran. Despite its fragility it is much prized and never seems to go out of fashion.
Unlike amethyst and topaz, tourmaline has escaped inordinate exploitation on the Brazilian market, probably because it is rarer and consequently more expensive. It is a mineral group of varying composition occurring in different colours, especially green, blue and grey. Pink specimens are known as rubellite.
A mineral of somewhat varying composition belonging to the silicate group. It is not a quartz and therefore has nothing in common with citrine quartz, a far less valuable stone. True topaz may be yellow, gold, pink, blue, green, mauve or red It does not reflect the light to any great extent; so the larger the stone the better. It is widely used in jewelry making and frequently imitated by citrine quartz.
Tiger's Eye, much like the eyes of a female cat, glitters with a small ray of light on the surface. This property of stone is known as chatoyancy. It is a brown quartz silicon dioxide having lustrous yellow and brown parallel fibers. The presence of iron oxides gives the stone the color of yellow-gold.
Sunstone or can be also called Heliolite, is the State Gem of Oregon, a prime source for this beautiful gem. The name Heliolite has been derived from the Greek 'helios' and 'lithos,' which mean 'sun' and 'stone'.
Sugilite is named after a Japanese mineralogist, Dr. Ken-Ichi Sugi, who discovered it in the year 1944 on the Iwagi Islet in Japan. The stone comes in pale to dark purple color and contains black, reddish brown and yellowy patches. Sometimes it also referred to Luvulite and Royal Lazelle. It belongs to the hexagonal crystal system.
Spodumene is a new mineral to science world discovered in the last three centuries. The gem variety of it was discovered only in the last 120 years. It is a lithium aluminum silicate with colors ranging from white, colorless, gray, pink, lilac, violet and green.
Sphen, means wedge shaped as it occurs normally, is a brilliant transparent yellowish-green or green with a high lustre and pronounced fire. It is also widely called as 'Titanium,' because of the titanium content in it. Titanium content sphen is often reserved for black or reddish brown non-gem quality material.
Sphalerite, also known as Blende, is one of the few minerals having six directions of cleavage. If six directions are perfectly cleaved on a single crystal, it forms rhombic dodecahedron. However, identifying the six directions in a single piece is quite difficult because of multiple twinning and the many directions. Only the abundant cleavage at different directions are seen easily.
Spectrolite is a variety of labradorite which displays intense reds, oranges and yellows and even blues and greens. These different colors are due to the light interference by thin lamellae, in parallel layers, within the spectrolite. The color play in the stone is iridescent as in the feathers of a peacock or the Northern Lights. It appears like a flash of light in the darkness.
Sodalite is named in reference to the sodium content it has. It is found in light to dark pure blue color and is well known in the semi-precious stone world. It is the only feldspathoid which contains chlorine.
Sillimanite is formed from aluminum silicate and is a transparent to translucent mineral ranging from white to gray, brown and green. It is mostly found as silky and fibrous masses with glassy luster. If it is not fibrous, the best field indicators are its crystal habit, color, brittleness and hardness.
Serpentine stone comes in staggering variety of colors. The variations in color is the result of varied mineral infusions in the stone. The name has been derived from the color and appearances of the stone which resembles the skin of a serpent. The best quality serpentine has fine textures with no cleavages.
Scapolite is commonly a mineral of metamorphic origin. It is grayish white which occurs in tetragonal crystals and in cleavable masses. For such color, it is sometimes also called Wernerite. It is a silicate of alumina and soda.
As I mentioned earlier, sapphire is corundum, too, and, its physical and chemical properties are virtually identical to those of ruby. In a natural state the gem crystallizes in the hexagonal system with two pyramidal faces. It is fractionally harder than ruby. Curiously, all corundums that are not rubies are classed as sapphires, which means that this particular gem exists in many colours, from blue to green, pink to mauve, white, grey, violet, yellow and orange.
Rutilite, also known as Rutile, is a mineral which consists of titanium dioxide, generally with a little iron. It is typically of reddish-brown in color, but deep red or black, with brilliant metallic or diamond-like luster is also seen.
Surprising as it may seem, ruby and sapphire, so different in colour, actually belong to the same mineral family: corundum, the mineral form of alumina which crystallizes in the hexagonal system. The red colour of ruby results from a small admixture of chromic oxide. The most prized tint is blood red or crimson known in the trade as "pigeon's blood" red. The colour of this corundum varies, however, according to the geographical locality of the mine. Siamese rubies, for instance, are of a deeper garnet red than those found at Mogok in Burma, while Ceylon ruby is of a pinkish dull red. Corundum is extremely hard, 9 on the Mohs scale. It is, therefore, not quite as hard as diamond but much harder than other minerals, including emerald. Transparent ruby, when cut en cabochon, may reflect light so as to produce star-like bands, a phenomenon rated highly by the experts. If viewed from a certain direction, bands of light are reflected onto the surface of the crystal forming a six-ray star shape. This optical effect is due to the presence of fine canaliculi or inclusions of rutile. The colour of these "starstones" varies from pale rose red, to deep crimson, to purple. Generally speaking, the darker the crystal, the less evident is the star, and vice versa. It is a rare gem indeed in which the colour and the star are of equal beauty.
Rubellite (Rubelite), a rare variety of tourmaline, comes in red color. It is more valuable than any other varieties of the red tourmaline. The name has been derived from the Latin word "rebellus," which mean "reddish." In gem trade, it is also known as "red tourmaline."
This widely diffused stone is often used for statuettes, carvings and other ornamental objects in the style of Chinese art. In the West it is cut en cabochon or as beads. Unfortunately, it faces strong competition from pink beryl, morganite, topaz and tourmaline.
Pyrite, commonly also known as "Fools Gold" because of its color and shape, is popular for its crystal habbit, hardness, streak, luster and brittleness. It is composed of iron disulphide having a pale brass-yellow color. The name pyrite has been derived from the Greek word, pyrites lithos, which mean 'stone which strikes fire,' in allusion to the sparking produced when iron is struck by lump of pyrite.
Prasiolite is a gem with which one can really be confused. It is traded with variety of names and sometimes mistaken with expensive gems like Green Beryl, Peridot and Tourmaline. The green variety is also named as Vermarine, Lime Citrine or Green Amethyst. Inexpensive, but a true collector's gemstone.
Peridot, the assigned stone for the summer month of August, is ancient but still very popular gemstone. Slightly golden shimmering green variety of it is ideal gemstone color to complement a light summertime outfit. It is formed of olivine, silicate found in igneous rocks, and a very good constituent of Earth's upper mantle.
Pectolite, as mineral, is confused with other minerals like okenite, wollastonite, artinite and few others. The name "Pectolite" has been derived from the Greek word "Pectos" which mean "well put together." This semi-precious stone occurs in white or colorless, gray, light yellow, light brown, light blue, and light pink.
Known as "queen of the oceans", pearl, like coral, is a victim of pollution. The name denotes a calcareous concretion with a silvery lustre formed within the shell of certain bivalve molluscs known as pearl oysters around some foreign body. There are two types: natural pearls, formed inside wild oysters, practically impossible to find nowadays, and cultured pearls in which the production of the pearl is artificially induced. Natural pearls have no nucleus, but in the cultured variety the pearl is formed round a spherical bead inserted into the oyster shell. The oyster tries to render this intrusive body innocuous by sealing it off in a cyst of nacre.
Opal, an amorphous form of hydrous silica, was once held to be unlucky, but maybe this was only because the stone is rather fragile and tends to chip and scratch easily. As it contains a high percentage of water, opal may deteriorate in heat and cold. Nonetheless, it is a very beautiful stone and, without wishing to contradict myself, it is even used as a lucky charm in certain countries.
This name is often erroneously applied to the alabaster, calcite and aragonite used in the manufacture of souvenirs and other ornamental objects sold throughout the tourist centres of the Mediterranean. True onyx is simply a black and white banded variety of quartz allied to agate. These bands being straight and parallel, onyx is sometimes known as "zebra agate" or, if the stone is completely black, "black agate". During the 1950s it was very popular as a stone for men's signet rings. It is now used for intaglios and cameos, necklaces and small pieces of jewellery.
Obsidian, also known as Apache tears, is a volcanic glass which is generally black, but is occasionally red, brown, gray, green (the rarest variety), dark with "snowflakes," or even very clear. It is said, probably to be the most challenging stone in crystal work. It is in fact a volcanic glass and has been used in past by many native cultures to make knives.
Nephrite in pure form is white in color or else green or creamy white. Sometimes even beige, yellow, blue or black is seen. It is a variety of jade, chiefly a metasilicate of iron, calcium, and magnesium. The green color in nephrite is due the presence of iron. Physically it is similar to chalcedony. Both have a fibrous structure.
The name is aptly given to the lustrous pearly lining of the shells of pearl-bearing molluscs.
Morganite, probably the best-known member from the beryl group, comes in many fine shades. The very fine pink color of the stone emanating charm, esprit and tenderness acts as a pure attraction, all over the world, for women. It was simply known as "Pink Beryl" previously.
A translucent variety of feldspar with a chatoyant quality, that is to say, having a changeable, undulating pearly lustre. It is either colourless or bluish-white and when cut en cabochon shows bluish gleams
Moissanite is said to be a rival to all other gemstone because of its brilliance, hardness, weight and scratch resistance. It possesses all the romance and passion of rubies, sapphires and emeralds. It is only found in meteorites and in a very limited areas beneath the earth's surface.
This hydrous carbonate of copper occurring in nature as an opaque stone, varying in colour from very light to very dark green. It has characteristic banding and is fragile and easily scratched.
The "sapphire" of classical times, it has always been a popular stone on account of its fine blue colour. It is really a rock consisting of varying quantities of a blue mineral hauyne and calcite. Small specks and strings of the yellow iron pyrites are common.
Labradorite, carries unique characteristic, turns sea blue, gold and green in bright light from grey or dark green color if viewed in dim light. It is a variety of plagioclase feldspar which is found in igneous rocks. Polished labradorite is called labradorescence. The crystal is transparent to translucent. The darker variety is known as "black moonstone" which has a bluish inclusions.
A variety of crystalline spodumene (a silicate of aluminum and lithium) generally of a lilac-pink hue, though yellow and green varieties are not uncommon.
The definition "jade" is used to define two minerals of similar appearance but different chemical composition: nephrite, a calcium- magnesium silicate, and jadeite, a silicate of sodium and aluminum.
This is a hard, white, elastic, fine-grained substance obtained from the tusks of the elephant, walrus, sperm whale and hippopotamus, this last variety being the best.
Iolite, the gemstone of the Vikings, is very often minstaken for Tanzanite. It is bluish violet in color where the prominent blue tone resembles blue sapphire and the lighter one, tanzanite. The name Iolite has been taken from the Greek word 'ios' which means violet.
Indicolite, also popular by the name Blue Tourmaline, is supposed to be the most colorful and rare variety of all the stones in gem world. The name 'Indicolite' has been derived from the Latin word for the indicum plant, famous due to its blue colors.
Hemimorphite is the commonly known sorosilicates which forms in oxidized zinc deposits and always occurs in clusters of radiating, acicular crystals. Originally, it was named Calamine, but since calamine is used for some other mineral, the word hemimorphit is widely in use. 'Hemi' means half and 'morph' means shape.
A widely-distributed iron ore occurring in crystalline, massive or granular forms. It is opaque and generally dark grey (almost black) in colour. It is cut en cabochon or as beads, though in Germany it is also used for intaglios. It is similar to steel in appearance, but much darker.
Heliodor (also spelt as helidor), a beryllium aluminum silicate is a golden yellow or golden green variety of beryl. The golden color is due to the presence of iron in place of aluminum in the structure of the crystal. In the gem world "golden beryl" is its other name. Sometimes it also contain a trace amount of uranium which make it slightly radioactive.
Goshenite is the colorless variety of beryl mineral group and is named after the site where it was first discovered, Goshen in Massachusetts. Sometimes it is also known as "white beryl" or "mother of gemstones."
The name given to a group of isomorphous minerals of different composition and colour.
Fluorite, a transparent and translucent stone which mean 'to flow' in Latin. The term 'florescent' also has been derived from fluorite. It is an attractive stone with a wide range of colors ranging from pink, purple, magenta, blue, yellow, green, red, brown and white.
