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)

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)

Gold: Gold is a Native Element that appears in very rare, small, octahedral, cubic, and dodecahedral crystals. It normally occurs in very small, shapeless grains, sheets, and flakes. Dendrites are rare. Nuggets are common in alluvial or glacial deposits. It is of yellow color, varying in brightness, depending on the impurities present. This bright, rich yellow is resistant to tarnishing. Gold is often (read full)

Rock Crystal (Quartz): Rock Crystal is the purest water-clear and colorless from of Quartz. It is known as mountain crystal (Bergkristall). It is the presence of impurities that gives other varieties of quartz their colors. It is found in beautifully formed crystals, often with complex terminations. These are usully bounded by the faces of six-sided prisms, which are almost always striated horizontally. Very often they (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)

Goshenite Beryl: Goshenite is a colorless sodium-rich gem variety of Beryl, a group which includes Emerald and Aquamarine. Other gem beryls include Heliodor and Morganite. It also appears are pale-green, apple-green, to bluish. All beryls are resistant to chemicals with the exception of fluoric acid. They are brittle and therefore easily damaged by knocks, have a vitreous luster, and occur with aquamarine. Their (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)

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)

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)

Milky Quartz: Milky Quartz is a milky white translucent to opaque variety of crystalline quartz of somewhat greasy luster. It is the commonest variety found in pegmatites and hydrothermal veins. The color is generally caused by numerous bubbles of gas and liquid in the crystal. The milky color is caused by small cavities filled with numerous small fluids and CO2 in liquid condition. It is used as a gemstone, a (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)

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)

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)

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)

Titanite: Titanite is a very rare calcium titanium silicate that is an important ore of titanium. It is also called Sphene. Its crystals are very rare, brilliant, and sparkles like diamond. It appears as crystals that are prisms with pyramid tips, or stubby, wedge-shaped, flattened crystals, or tabular and platy. There are also titanite crystal twins that have grown side by side or interpenetrated, or in g (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)

Zoisite: Zoisite is a hydrous calcium aluminum silicate in the Epidote group, with an orthorhombic crystal system, three crystal axes at right angles to each other, all of varying lengths. It appears in elongated, prismatic crystals, with fine parallel lines on the prism faces and usually poorly terminated. It also appears frequently in formless grains, poorly-defined crystals, rodlike aggregates and gran (read full)