Pyrope: Pyrope is the iron magnesium and aluminum silicate of the pyrope-almandine series in the Pyralspite group of the Garnet family. Its beautiful deep-red gem quality makes it one of the most popular. Pure pyrope is colorless, but its red color, sometimes very bright, is due to small quantities of chrome in the crystal structure. It appears as dodecahedral or trapezohedral crystals, dark red, usually (read full)

Opal: Opal is hydrated silicon dioxide. It has the same chemical composition as quartz but contains about one-tenth (and sometimes as much as one-third) water. It is never crystalline, but it displays a rich play of colors, or "fire" caused by the internal refraction of light by the array of tiny spheres of amorphous silica which for a compact, three-dimensional network in the mineral. It may be somew (read full)

Almandine: Almandine or Almandite is a member of the Garnet group, and is associated with the planet Pluto. Low quality pyrope is often cataloged and sold as Almandine. Almandine is generally darker than pyrope. Almandine colors vary from red to dark red, purple to purplish red, and even pink. Almandine is valued fairly low at somewhere between $5 and $225 a carat all dependent upon clarity, color, cut, an (read full)

Grossular Garnet: Grossular is a nesosilicate in the Garnet group, with an isometric crystal system. Together with uvarovite and andradite, the three are known as the "ugrandite garnets," an isomorphous series of calcium garnet minerals. It appears with dodecahedral or trapezohedral crystals of various colors; normally characterized by a green color, but also may be colorless, pale green or milky when pure, cinnam (read full)

Unarovite: Uvarovite is a rare, calcium-chromium emerald-green variety of Garnet. Together with grossular (calcium-aluminum) and andradite (calcium-iron), it makes up the series of ugrandite garnets. These three have similar crystal structure and form, but just have different chemical proportions. It occurs in mixed crystals, so there is a partial replacement of some elements by others. It stands out from t (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)

Coral: Corals are the supporting framework of small polyps. Each coral polyp, a tiny marine animal that lives in enormous colonies, extracts calcium carbonate from the sea and exudes it through their bases 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. They precipitate calcareous m (read full)

Andradite: Andradite is a name given to members of the garnet that contain manganese and titanium. The 3 types Andradite are..1.)Demantoid, 2.)Melanite, and 3.) Topazolite Demantoid-the word means diamond like. It is yellow green to green in color and is the most valuable of the 3 types. Demantoid is soft enough that older gems will have facet edges that are slightly worn. Largest deposits (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)

Platinum: Platinum is a rare and precious metal that occurs as a Native Element, one of the rarest in the Earth's crust. It resembles silver, but it is less reactive and does not tarnish in air, and is thus considered a noble metal. Its greater hardness, higher density, and high melting point also distinguish it from silver. Like gold, another noble metal, the only common acid combination to dissolve it i (read full)

Morganite: Morganite is a pale red-purple, rose, salmon to purplish red, slightly pink, cesium-bearing variety of Beryl. The Beryl group of silicates includes the important gem varieties emerald, blue aquamarine, pink morganite, and red and yellow beryl. The color of morganite is usually a soft pink without any overtones. It has glassy luster, like other beryls, but its pleochroism is not noticeable. The p (read full)

Iolite: Iolite is the violet-colored variety of Cordierite (named after French geologist P. Cordier), a silicate of aluminum and magnesium, with an orthorhombic crystal system. Though the name cordierite is used by mineralogists, the name iolite has become established among gemologists. It appears as stubby, prismatic crystals, pesudo-hexagonal twins with a glassy appearance. It is frequently microgranul (read full)

Sphalerite: Sphalerite is a zinc iron sulfide mineral formed in an isometric system. It is trimorphous with wurtzite and matraite. All three have the same chemical compound but crystallize in three different forms. The most common crystal forms of sphalerite are in dodecahedrons and tetrahedrons, elegant three-sided formations, often twinned, and otherwise usually massive, thus looking like brownish-black or (read full)

Hessonite: Hessonite is the brown-orange variety of Grossular, a nesosilicate in the Garnet group, with an isometric crystal system. It appears with dodecahedral or trapezohedral crystals, cinnamon-brown to orange because of its iron content. Its color matches that of the oil of cinnamon. It also appears as golden-yellow, yellow-brown, or reddish-brown. It is very hard, heavy, fragile, has no cleavage. It (read full)

Lazulite: Lazulite is a compact, pleochroitic mineral which forms a series to scorzalite. It is dichroic, with a monoclinic crystal system. It appears as pointed, pseudo-dipyramidal, bright blue crystals in microgranular masses. It is hard, medium heavy, fragile with indistinct prismatic cleavage. It is translucent, with vitreous luster. It is infusible, discolors and breaks into small fragments when heat (read full)

Silver: Silver is a Native Element with an isometric system, a soft, white, precious metallic element of group 1 of the Periodic System with the symbol Ag. It appears as cubes, octahedrons, and dodecahedrons, and rarely as crystals. Native silver cubes are always small, usually displaying stepped faces, or in compact masses of twining branches, and wirelike forms of a silvery, gray-white color. Aggregate (read full)

Staurolite: Staurolite is a hydrous magnesium aluminum silicate that crystallizes in the monoclinic system. It appears as coarse, dark gold-brown prisms, or sometimes reddish-brown to black stubby crystals. On weathered rock, it stands out in contrast like sand-coated yellowish brown prisms. Surfaces are often rough or covered with an earthy coating because of natural alteration. It frequently occurs in ch (read full)

Serpentine: Serpentine may refer to a single mineral but more often to a group of minerals including antigorite, chrysotile, clinochrysotile, and lizardite, which are altered products of basic and ultra-basic rocks. Rock composed of these minerals is called serpentinite. It comes in all the hues of green.
In mineralogy, serpentine is divided into three polymorphs, crystals with the same chemical substanc (read full)

Vesuvianite: Vesuvianite is a hydrous calcium magnesium aluminum silicate with a tetragonal crystal system. It is the preferred name used by mineralogists for all transparent varieties of Idocrase, the name used by gemmologists. It is a gem mineral that appears in diverse colors, and thus is prized by collectors. A compact green variety of vesuvianite that looks like jade is known as californite. A greenish-b (read full)

Taaffeite: Taaffeite is a very rare beryllium magnesium aluminum mineral. No other mineral has both beryllium and magnesium in its composition. It is one of the few gems to be discovered as a faceted stone instead of a rough, as most gemstones are. Rarely cut as a gem, taaffeite looks like a mauve-colored spinel, and its absorption spectrum is similar to it. But gemologists know they've found taaffeite when (read full)

Kyanite: Kyanite is an aluminum silicate that occurs as elongated and tabular in groups of light-blue crystals darker toward the center, or flat, bladed crystals in schists and gneisses, or as radiating rosettes in quartz. It is trimorphous with sillimanite and andalusite. Kyanite is also known as disthene, meaning, "double strength." This refers to the fact that the hardness along the length of kyanite c (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)

Rose Quartz: Rose quartz is a usually cloudy, translucent, delicate pale pink, deep pink, rose-red to quasi-white and often veined variety of Quartz. Also known as pink quartz , rose quartz may occur more often as anhedral masses or rarely as crystals which often reach quite large sizes. Rose quartz almost always occurs in pegmatites in massive crystalline bodies which do not show crystal faces. These larg (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)

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)

Zircon: Zircon is a zirconium silicate with a tetragonal crystal system, and also contains thorium and uranium. It appears as stubby, prismatic, isolated or sometimes dipyramidal, like two pyramids connected at their bases; or in twins, colorless to yellow, red, brown, gray or green, in irregular granules. It is very hard, heavy, with indistinct cleavage, and shell-like fracture. It is sometimes perfect (read full)