Amblygonite: Amblygonite is a not so popular gem whose greek name means crooked. It comes in green, clear, yellow, and even purple. Older cut specimens may have slightly rounded facet edges due to the gems lack hardness (6 of 10). Amblygonite can be found in Brazil, France, the United States, Burma, and even Sweden. It may be confused easily with Brazilianite. (read full)

Chatoyant Quartz: When quartz contains similarly-oriented fibrous inclusions, and is then appropriately-cut, in cabochon, curved stones display what is known as chatoyancy, meaning 'like a cat's eye.' The result is a series of minor gemstones differing only in their ground color and the mobile reflection. Comes in colors white, gray, green, yellow, brown. When the ground color is greenish-gray or green, the gem (read full)

Jadeite: Jadeite is a silicate of sodium and aluminum, and is a member of the Clinopyroxene group of minerals. It is so called because it is the source of one of the ornamental materials commonly known as Jade. It has a monoclinic crystal system, and occurs as granular aggregates of small crystals, but has occasionally been found in crystals of a few centimeters. The color varies a great deal because of t (read full)

Epidote: Epidote is widespread, forms a continuous series of minerals, ending with clinozoisite, which contains no iron. It occurs as crystals elongated and often striated parallel to length, and also as massive, fibrous, or granular habits. Epidote has a yellow-green color, ranges from yellowish-greenish to greenish-black. It has vitreous luster, and is transparent to nearly opaque. It has one perfe (read full)

Spinel: Spinel is an extensive group of minerals in which magnesium may be replaced with iron, zinc, and above all, manganese. The hardness and fine colors of gem quality spinel, known as Noble Spinel, set it apart as a gem material from other types of spinel. It normally occurs as distinct octahedral crystals, as clusters also of octahedral habit, or as characteristic twins. The crystals are often iso (read full)

Sinhalite: Sinhalite is a magnesium aluminum borate, and is most commonly found as transparent honey-yellow to brown grains or pebbles with an orthorhombic crystal system. It also appears as pale yellowish, yellow, brown, greenish-brown to black. It occurs in contact metamorphic rocks that are rich in boron, among gneiss or granite where limestones are being replaced through contact with magmatic rock. But (read full)

Ruby: Ruby is the most valuable variety of Corundum. The color varies from fiery vermilion to violet red, but because rubies are pleochroic, different colors are also found in the same stone; bright or sometimes brick red in one direction, tending to carmine in the other. The color is also accompanied by marked fluorescence which is stimulated by ordinary, artificial light, and above all, by the ultra (read full)

Scapolite: Scapolite is a mixed crystal series, a complicated sodium calcium aluminum silicate group composed of calcium-rich meionite, and sodium-rich marialite. It appears as yellow, blue, pink, violet, or colorless prismatic crystals with a tetragonal system, mostly surface-growing, with perfect cleavage. These crystals are usually in aggregates that are massive granular, long columnar, dense, with vitr (read full)

Danburite: Danburite is a silicate of clear, prismatic crystals, with wedge-shaped terminations. It is occasionally pale yellow, a variety of gemstone feldspars group that resembles topaz. It is very hard, heavy, and has a transparent to vitreous to greasy luster. It fuses easily into a colorless glass, coloring the flame green, has a luminescence that is sky blue to pale blue-green, and also shows red therm (read full)

Sapphire: Sapphire is the blue variety of Corundum. Sapphires can be a very dark blue, to the point of seeming dense and blackish from a distance, sometimes accompanied by a blue to dull green pleochroism, which is only visible from the side in cut stones. They may also be a strong, but not too bright blue, easily recognizable from a distance, this being the real color. Other possibilities are light, usual (read full)

Padparadscha: Padparadschah is the name given to the orange-yellow sapphire, a gem variety of Corundum. It is also differentiated from the yellow sapphire, and is one of the rarest varieties of corundum. The main sapphire-bearing rocks are marble, basalt, or pegmatite. It is mined mainly from alluvial deposits or deposits formed by weathering, rarely from the primary rock. It usually occurs in placer deposit (read full)

Peridot: Peridot is the greener type of gem-quality specimen of Forsterite-Olivine, which is an important, rock-forming mineral, a silicate of magnesium and iron. Often their names are used interchangeably. The bottle-green/olive green type of olivine is also called olivine. The yellower type of olivine is called Chrysolite. It forms as thick, tabular crystals, frequently with wedge-shaped terminations. T (read full)

Schorl Tourmaline: Schorl is the black, opaque, sodium iron rich variety of Tourmaline, a complex borosilicate with a trigonal crystal system.
Tourmalines usually occur as long, three-sided prisms, which often have well-terminated ends. Sometimes they are found as parallel or radiating groups of long, thin prisms with striated ridges lining its surface. Its varieties span the widest color ranges in the mineral (read full)

Rubellite Tourmaline: Rubellite is the pink to red variety of Tourmaline, which is a complex borosilicate of aluminum and alkali, with iron, magnesium, and other cations. It is found as fine acicular crystals in rocks, or as large individual crystals grown upon matrix where they may reach a weight of several kilograms. Most form elongated and striated trigonal (three-sided) prisms and these are terminated with trigona (read full)

Ivory: Ivory is an organic gem material, largely obtained from the tusks of African and Indian (Asiatic) elephants, but also from the teeth and tusks of the hippopotamus, walrus, and other mammals. Like bones, it consists mainly of calcium phosphate in the form of oxyapatite and a small quantity of calcium carbonate, bound together by large amounts of the proteinaceous organic substance dentine, to form (read full)

Lapis Lazuli: Lapis lazuli is composed of several minerals in small quantities - augite, calcite, diopside, mica, hauynite, hornblende, pyrite. Because of this some experts consider it a rock, more than a mineral. The main ingredient of Lapis lazuli is Lazurite. It has a uniform, massive, or sometimes granular appearance, with fairly distinct crystals. It is semi-opaque to opaque, with a surface that can take (read full)

Nephrite: Nephrite is a silicate of calcium, magnesium, and iron, containing fluorine and hydroxyl. It is an amphibole of the actinolite series. It occurs in all colors, also striped and spotted, but the most valuable color is green. The amphiboles of the tremolite-actinolite series usually occur as elongated, parallel, radiating, or even fibrous crystals; but the variety known as nephrite has a very compa (read full)

Scheelite: Scheelite is a mineral in the group of Sulfates, Chromates, Molybdates, Tungstates. It has the same crystal structure and outside appearance as powellite. But scheelite is a calcium-tungstate, while powellite is a calcium-molybdate.

In rocks, scheelite may appear as crystals like two pyramids connected at its bases, or pseudo-octahedral, or having table-like faces, with detectable p (read full)

Sillimanite: Sillimanite is a grayish-blue aluminum silicate with an orthorhombic crystal system. It is trimorphic with andalusite and kyanite. All three have the same chemical compound but their atoms each arrange to create three different crystal forms. It appears as long, slender crystals without distinct terminations, in off-white, gray, brown, pale green, slate-blue, blue-green, and these crystals are of (read full)

Enstatite: Enstatite is the most common silicate under the Orthopyroxene group in the larger classification of Pyroxene minerals (which are rock-forming silicates). Orthopyroxenes form a chemical series composed of the magnesium-rich enstatite, and the iron-containing bronzite and hypersthene. It has an orthorhombic crystal system and appears rarely as stubby, prismatic crystals, but more commonly in fibr (read full)

Sodalite: Sodalite is a sodium aluminum silicate chloride in the Sodalite group with an isometric crystal system. Its royal blue forms are the best known. As a mineral, it is a principal component of lapis lazuli. It appears very rare as dodecahedrons, crystals with 12 faces, but usually it shows as compact masses, bright blue, white or gray with green tints. It is unsaturated and rarely appears with inclu (read full)

Spessartine: Spessartine is the manganese-aluminum variety of Garnet, belonging to its sub-group of aluminum garnets. Garnets are a group of silicate minerals that all crystallize in the isometric system and have the same chemical formula, but in a diversity of proportions, so garnets show up as different varieties, in a broad range of environments. Spessartine possesses the form typical of garnet crystals, w (read full)

Diopside: Diopside is a type of Clinopyroxene, which are abundant, rock-forming minerals. These are embedded and surface-growing crystals, short columnar, and tabular, almost square or octagonal in cross section. It is the magnesium-bearing end member in the isomorphous, monoclinic diopside-hedenbergite series, a complete solid solution series in which two intermediate members, salite and ferrosalite, have (read full)