Axinite: Axinite is a honey brownish to dark brown gem that is named after the axe head like crystal structures that are usually found. It is usually found in and around granite deposits, and is often mistaken (and sometimes sold by mistake) as smokey quartz. The gem is piezoelectric and because of this has been used to remove hair and lint from unwanted objects. A negative side effect of this is that it (read full)

Celestine: Celestine appears as colorless, or pale blue, and is transparent to translucent, and has two directions of cleavage. It is very brittle, and has a vitreous to pearly luster. It occurs in sediments associated with sulfur, with evaporate minerals like gypsum, anhydrite, and halite; in hydrothermal veins with galena and sphalerite; as concretions in clay and marl; in cavities in basic lavas, and i (read full)

Chalcedony: Chalcedony is a compact form of silica, composed of microscopic quartz crystals. It is softer than quartz and denser than opal. Its appearance may range from transparent to translucent to opaque. The main types are chalcedony, which is uniformly colored, and agate, which has curved bands or zones of varying color. Varieties include the red to reddish brown, translucent carnelian, the red, opaqu (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)

Chrysocolla: Chrysocolla is a silicate that forms as stalactitic masses, in radiating groups, or closely-packed aggregates. It appears as green, blue, and blue-green, but can also be brown or black when impurities are present. It may be translucent to nearly opaque, and has a vitreous to earthy lustre. It forms in the oxidation zone of copper deposits, and occurs with azurite, malachite, and cuprite. When d (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)

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)

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)

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)

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)

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)

Gypsum: Gypsum is the most common sulphate mineral. It is usually the first evaporite mineral to be precipitated form water due to its poor solubility. Varieties include Selenite (or "spectacle stone), which is colorless and transparent; Satin Spar, the fibrous, translucent form with silky luster, which when cut cabochon shows pearly chatoyant effects; Alabaster, used for ornaments, which is firm, fine-gr (read full)

Emerald: Emerald is the most prized variety of the mineral Beryl. It sometimes fetches higher prices than diamond. It appears as pale green to bright green. Though it is the green variety of beryl, not all gem-quality green beryls are called emeralds; yellow-green stones are called "heliodors;"soft blue-green or even pale green specimens are called "aquamarines." The typical color of emerald is a bea (read full)