Posted by QuickReadAbout.com Staff in The precious stones are very well known. They are diamonds, rubies, sapphires, and emeralds. Some of the semiprecious stones aren’t quite as well known, but they are very beautiful, and each has its own special features. Here is a list:
Agate: an impure form of quartz consisting of banded chalcedony. Alexandrite: A greenish chrysoberyl that appears red in artificial light.
Amethyst: A purple or violet form of transparent quartz.
Aquamarine: A transparent blue-green variety of beryl.
Chrysocolla: A hydrous silicate of copper, occurring massive, of a blue or greenish blue color.
Chrysoprase: An apple-green chalcedony.
Feldspar: Any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium.
Garnet: Any of several common, widespread aluminum or calcium silicate minerals occurring in two internally isomorphic series, generally crystallized, often embedded in igneous and metamorphic rocks, and colored red, brown, black, green, yellow, or white.
Hematite: A black or blackish-red to brick-red mineral, the chief ore of iron.
Jade: Either of two distinct minerals, nephrite and jadeite, that are generally pale green or white.
Jasper: An opaque cryptocrystalline variety of quartz that may be red, yellow, or brown.
Kunzite: A lilac-colored spodumene.
Lapis lazuli: An opaque to translucent blue, violet-blue, or greenish-blue semiprecious gemstone composed mainly of lazurite and calcite.
Malachite: A green mineral.
Obsidian: A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava.
Olivine: A mineral consisting of magnesium iron silicate; a source of magnesium.
Opal: A gemstone made of this mineral, noted for its rich iridescence.
Pyrite: A common mineral (iron disulfide) that has a pale yellow color and is also known as Fool’s Gold.
Quartz: Colorless glass made of almost pure silica.
Spinel: A hard, variously colored mineral, having usually octahedral crystals and occurring in igneous and carbonate rocks. The red variety is valued as a gem and is sometimes confused with ruby.
Tanzanite: A transparent variety of zoisite.
Topaz: A colorless, blue, yellow, brown, or pink aluminum silicate mineral, often found in association with granitic rocks and valued as a gemstone, especially in the brown and pink varieties.
Turquoise: A blue to blue-green mineral of aluminum and copper.
Tourmaline: A complex crystalline silicate containing aluminum, boron, and other elements, used in electronic instrumentation and, especially in its green, clear, and blue varieties, as a gemstone.
Zircon: A brown to colorless mineral which is heated, cut, and polished to form a brilliant blue-white gem.