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Gemstone Crystal System Density Hardness Refractive index Treatments
Apatite hexagonal 3.2 5 1.63-1.640 heat



Blue, colorless, pink, green, yellow, yellowish green, greenish brown, reddish brown, violet and cat's eye varieties.

Clarity: Transparent to Translucent
Optic Character:
uniaxial negative
Cause of Color: Undetermined

Blue: Blue to light blue (LW and SW)
Yellow: Purplish Pink (stronger in LW)
Green: Greenish-yellow (stronger in LW)
Violet: Greenish-yellow (LW);Light purple (SW)

Fracture : Concoidal

Luster : Vitreous
Cleavage :
Imperfect basal
Durability: Fair

Characteristics for Identification:
Spectroscope can seperate from tourmaline and topaz.

Brazil, Burma, Mexico
Violet and Purple are found in Maine and Afghanistan.


Apatite is a calcium phosphate always containing traces of fluorine and chlorine. Until its color being compared to Paraiba tourmaline, it was really a gem for collectors and never seen in the commerial marketplace. Beautiful blue stones are found in the Mogok Stone tract of Myanmar and in the gem gavels of Sri Lanka. Dichroism in apatite is usually feeble (as the birefringence is .002-.004) but somewhat distinct with the exception of the blue and some of the green gems.

One of the most interesting features about apatite is that it's composition is very close to that of teeeth.


Above is a cluster of apatite crystals from Afghanistan and below a rare faceted violet colored apatite:
Courtesy of Jason Brim