An Appetite For Apatite? |
The public is not as familiar with apatite as are collectors. It is actually made of three minerals, mainly fluorsapatite, chlorapatite, and hydroxyl apatite. It is a member of the Apatite Group of hexagonal crystals. It is usually green (called an asparagus stone) but also comes in reddish brown, blue, yellow, colorless, violet, and purple, sometimes with a white streak. Some have many colors, and look as if they are illuminated. After heating it can become an orange/yellow color. A cat's eye affect occurs when rutile has grown in the crystals. The more vivid the color, the more valuable the apatite, with green being the most desired. The asparagus green stones and manganapatite with its bluish hue are used in jewelry.
Its hardness on the Mohl's scale of hardness is 5, so it is half as hard as a diamond. Because of its softness it is not often used for every day jewelry, but if care is taken it can be used occasionally. The stone has an uneven surface as if part of it has been bitten, and is sensitive to acid. Apatite has a greasy luster.
The word apatite came in 1788 from the Greek word "apate" meaning "deception" or "I am misleading" because it can be mis-identified as tourmaline, quartz, olivine, phenakite, peridot, and other stones. Collectors love apatite and some even have the stones faceted to make them even more beautiful.
Phosphorous is extracted from huge deposits of rock containing apatite, and used for phosphate fertilizer. When impure and in large quantities it is called phosphorite. It also has other uses in industry. Apatite is quite common and can be found in Tunisia; Egypt; Durango, Quebec; Mexico; Ontario, Canada; Kenya; Sri Lanka; South Africa; Hebron, Maine; the United States; India, Norway; Russia, Morocco, Algeria, Nauru, San Diego County, California; Czechoslovakia; Spain; Austria, Portugal. Isarel, and Germany. Some of these sites are known for their widespread deposits which are mined to use in industry, as those in Tennessee, Wyoming and Idaho.
Apatite can be found in igneous rocks (such as pegmatite), metamorphic rocks (such as marbles) and sedentary rocks, but is a minor player. The larger crystals are often found in metamorphic rocks. Some stones are faceted, while others are cut into cabochons. It is one of few minerals used by micro-environmental systems, and is the most common phosphate mineral crystals range from transparent to translucent. It is also the mineral which comprises the teeth and bones in all vertebrae animals.