Agate Chalcedony: Agate Chalcedony differs from other Chalcedony in that it often has distinct banding. In fact some slices of Agate may appear to have banding similar to that of tree rings. Due to its porous nature it is often colored (by humans) black, red, green, or blue to further increase its visual appeal. Agate Chalcedony is found in Brazil, China, Germany ,Hungary, Mexico, Uruguay, the United States, and (read full)

Datolite: Datolite is a semi rare silicate mineral of the gadolinite group. It appears as surface-growing, short and stubby, prismatic, large crystals. Its crystal structure is monoclinic, as it has two axes of unequal length inclined to each other, with the third lateral axis at a right angle to the plane that contains the other two. Its aggregates are huge, granular, dense, fibrous, and has porcelaneou (read full)

Andalusite: The gem Andalusite is a gemstone composed of Lead Sulphate giving it a yellowish hew with a light tint of a rusty red color. Its named after the city Andalusia in Spain where it was first found. Colors generally vary from yellow, to yellow green, to green, to brownish red (more iron in the read hued versions), to purple, and even black. This gem is pleochroic meaning it changes color depending on (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)

Chrysoprase: Chrysoprase is a massive, translucent, dull leek-green to yellow-green compact quartz aggregate, a variety of chalcedony. It is a crystalline quartz leek-green in color containing swarm of green hair-like fibers amphibole actinolite, which is responsible for green color. Its color is caused by fibrous ferrohornblende aggregates or disseminated chlorite minerals. The stone is more translucent than (read full)

Rhodochrosite: Rhodocrosite is a manganese carbonate, a mineral of the calcite series with a hexagonal crystal system. It is isomorphous with calcite and siderite. It occurs as semitransparent, rhombohedral crystals with poor luster, frequently saddle-shaped, growing into druses, or as concretionary masses, sometimes with irregular, contorted veining. It has low hardness and perfect rhombohedral cleavage. Norm (read full)

Phosphophyllite: Phosphophyllite is a very rare mineral, a hydrated zinc iron manganese phosphate with a monoclinic crystal system. It appears as long prismatic or thick tabular crystals. It is colorless to deep bluish-green. Polysynthetic twinned crystals are common. It is semi-hard, light, with excellent prismatic cleavage. Translucent to transparent with vitreous luster. It turns gray and loses water when hea (read full)

Chrysoprase: Chrysoprase is a variety of chalcedony, usually black or leek-green in color. The most highly-prized variation comes in bright-green, apple- or leek-green. It has a waxy lustre. It occurs as mammillary or botryoidal masses. The microscopic quartz fibers have a radial structure. The pigment is nickel. Large broken pieces are often full of fissures with irregular colors. Its color can fade in sun (read full)

Cassiterite: Cassiterite may form as short or slender prismatic, or bipyramidal, elbow-shaped crystals. It has a crystal surface reflecting light as in a mirror. They may occur as massive, granular, botryoidal, and reniform. When found in granular, banded, fibrous masses, it looks like wood. When found in groups of large bright crystals, it is usually called "diamond tin." A red variety cut for collectors is k (read full)

Orthoclase: Orthoclase mineral is a silicate of potassium and aluminum, belonging to the Feldspar group. It has the same composition as microcline, but is stable at slightly higher temperatures. It occurs as prismatic, sometimes flat-sided crystals, but in rocks it is usually anhedral. It may be perfectly transparent and yellow or almost colorless, but it is more often semi-opaque and white to grayish-white, (read full)

Cerussite: Cerussite is a colorless carbonate of the aragonite mineralogical classification. It appears as colorless or white crystals with grayish tints, elongated and generally twinned to form a reticulated network with 60-degree angles, as stubby, tabular crystals in star- or heart-shaped twins. It can also be grey, greenish, or blue as a result of inclusions, such as lead, or copper. Impure cerussite is (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)

Dolomite: Dolomite is similar to calcite and sits along side it in limestone. It usually occurs as a secondary mineral, formed by the reaction of magnesium-bearing fluids seeping through the limestone. It may be colorless, or white to cream and even yellow brown, sometimes pale pink. It has a vitreous luster and is translucent. The faces of dolomite crystals are often curved, sometimes so acutely that th (read full)

Hematite: Hematite is considered the most important Iron Ore mineral. Its crystals appear as reasonably thick. They may be tabular, or rhombohedral, and occasionally prismatic or pyramidal. Tabular crystals may form as rosettes, when they are called "iron roses." It also occurs as massive, compact, columnar, fibrous, reniform, botryoidal, stalactitic, foliated, and granular. When hematite forms in a renif (read full)

Jet Lignite: Jet is an organic gem material composed of lignite, and is a bituminous coal which can be polished. It is compact, homogeneous, has a hard, glossy surface and black interior variety of fossilized lignite or coal. It is an opaque black coalified fossilized drift wood from the coniferlike, 180 million years old 'Araucaria' or monkey puzzle tree that has been dried and fractured following death of (read full)

Pyrite: Pyrite is an iron sulphide mineral with a cubic crystal system and is dimorphous with marcasite. It occurs as cubic crystals with striated faces, or in the form of pentagonal dodecahedra, usually well-crystallized, either isolated or in small, often well-formed groups, or as "iron cross" twins. It is a characteristic, brassy-yellow or pale-gold color, opaque and with a metal luster. It sometimes (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)

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)

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)

Malachite: Malachite is a bright green, basic copper carbonate. It appears as fibrous, radiating aggregates with silky to dull luster, and its crystals are adamantine. Acicular crystals are common. It commonly occurs as a green film on other copper minerals and as botryoidal or reniform masses with concretionary, banded structure and emerald green color. The color of the glassy, lustrous crystals is dark (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)

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)

Jasper Chalcedony: Jasper is the opaque form of Chalcedony, the microcrystalline varieties of quartz that form concretionary deposits, partially of organic origin in the case of jasper. It is commonly microscopically fibrous, massive, and has a nearly wax-like luster. It has a lower density than ordinary quartz. It is the archetypal collectable beach pebble, dense, fine crystalline, translucent to opaque, and cons (read full)

Fluorite: Fluorite is a widely-distributed mineral in the Halide classification, and is now mined in vast quantities. It is a suitable mineral for collectors and is rarely cut as a gem, but massive varieties are carved as ornamental objects. It appears in cubes, octahedrons, dodecahedrons, while other forms are rarer. Compact, banded, and concretionary masses are frequently found. Most fine crystals of flu (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)

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)