Apatite

Not to be confused with appetite, the desire to eat.

Apatite is a group of minerals are written as Ca₅(PO₄)₃(OH), Ca₅(PO₄)₃F and Ca₅(PO₄)₃Cl, respectively.

Apatite is one of few minerals that are produced and used by biological micro-environmental systems. Hydroxylapatite is the major component of tooth enamel. A relatively rare form of apatite in which most of the OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material.

skeletal fluorosis.

In the United States, apatite is often used to fertilize tobacco. It partially starves the plant of nitrogen, which gives American cigarettes a different taste from those of other countries.

Fission tracks in apatite are commonly used to determine the thermal history of orogenic (mountain) belts and of sediments in sedimentary basins.

Phosphorite is the name given to impure, massive apatite.

Gemology

Apatite is infrequently used as a moroxite.^[3] Crystals of rutile may have grown in the crystal of apatite so when in the right light, the cut stone displays a cat's eye effect. Major sources for gem apatite are^[1] Brazil, Burma, and Mexico. Other sources include^[1] Canada, Czechoslovakia, Germany, India, Madagascar, Mozambique, Norway, South Africa, Spain, Sri Lanka, and the US.

See also

• List of minerals
• Thermal history modelling

References

1. ^ ^{a b c d e f g h i j k l m n o p} Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
2. ^ ^{a b c d} http://webmineral.com/data/Apatite.shtml Webmineral data
3. ^ Streeter, Edwin W., Precious Stones and Gems 6th edition, George Bell and Sons, London, 1898, p306

• Apatite on Mineral galleries

Further reading

• Schmittner Karl-Erich and Giresse Pierre, 1999. Micro-environmental controls on biomineralization: superficial processes of apatite and calcite precipitation in Quaternary soils, Roussillon, France. Sedimentology 46/3: 463-476.