Mineral spotlight: Apatite


Photo by Camille VanderVeen.

Hopefully your Thanksgiving was a pleasant one, filled with lots of turkey, stuffing and all the works. At the Dice Mineralogical Museum, we sure had a large apatite.  

Though the mineral itself may not be appetizing to eat, the teeth and bones of humans are composed of the same material as apatitecalcium phosphate.  Apatite is the most common phosphate mineral. It can be found in phosphorite, a rock mined for its phosphorus content, which is a main source of the phosphorus used by plants.

Phosphorus is also commonly used in pesticides, detergents, fireworks and explosives.  Phosphorite is necessary to produce enough food to feed the world’s growing population. Without phosphorite, we would not have enough fertilizer to meet the world’s demand. You can thank apatite for satisfying your appetite.

Apatite is not actually a specific mineral, but is the name given to the group of phosphate minerals that have similar physical properties and chemical compositions. Apatite was named by German geologist Abraham Gottlob Werner in 1786. He named the mineral after the Greek word that means “deceit.” It received this name because of its comparable, and sometimes confusing, appearance to many other minerals.

In the late 1960s, during the Apollo Program, moon rocks were collected that contained traces of apatite. The samples were of hydroxyapatite, containing trapped water that allowed astronomers to make estimates of the amount of water on the lunar surface. The water on the surface was estimated to be at least 64 parts per billion. If the water found in apatite was in the liquid phase, the moon would be covered in one meter of water. Though these estimates have since been revised, apatite allowed us to collect data on the moonEarth’s only natural satellite.

Fluorapatite is the most common form of apatite, and is sometimes used for water fluoridationthe process of adding fluoride to water to strengthen tooth enamel. Though the hardest material in the human body is tooth enamel, apatite is not particularly hard. It serves as the index mineral for a medium hardness of five on the Mohs Hardness Scale. Apatite varies in color but is usually green. It can also be pink, yellow, blue, brown, purple or colorless. These colors can be vibrant, so apatite is frequently cut as a gemstone.

However beautiful, apatite is a brittle mineral and is susceptible to wear from chemicals and acids, so jewelry is usually confined to earrings or occasional-wear rings.

Apatite is mined in many locations around the world, the most common locations being Brazil, Burma and Mexico. To see apatite up close, come visit the Bruce Dice Mineralogical Museum, open every Wednesday, Thursday and Friday from 12:30-4:00 pm.