Apatite

Group name for the minerals fluorine-, chlorine- and hydroxyl-apatite.
Apatite is the reference stone for hardness 5 in Mohs´ scale of hardness.

Apatite shop

Name: greek: απατείν apatein = to deceive

Can be confused with: because of the wide range of colours apatite can be confused with many other minerals. Some blue and green apatites from Madagascar bear a striking resemblance to the famous Paraïba tourmalines

Localities: Very common worldwide. Commercially important sources are Madagascar, India, Sri Lanka, Burma, China, Brazil, Mexico and the USA.


Apatit aus Brasilien
Apatite from Brazil

Apatit aus MadagaskarApatit aus Madagaskar
Apatit aus MadagaskarApatit aus Madagaskar
Apatites from Madagascar

Handling: No distinct cleavage but very brittle and sensitive to pressure.
Very sensitive to heat and acids, solder with care!
Do not clean ultrasonically! No galvanic treatment!
Because of the low hardness and the sensitivity to shock and pressure apatite is not recommended for use as a ringstone.
Apatite is a difficult customer to cut. From experience we reckon it´s chances to survive a lapidary repair job to be below 50%!

Worth knowing: Due to the very attractive colours and the relatively low prices apatite enjoys growing popularity. The colours of light green and blue apatites, in particular, match the colours of the finest Paraïba-tourmalines. If only it weren´t for the low hardness and the high sensitivity…

Apatite shop

Gemmological Properties of Apatite

Formula:
Fluorine-Apatite: Ca5(PO4)3F    
Chlorine-Apatite: Ca5(PO4)3Cl    
Hydroxyl-Apatite: Ca5(PO4)3OH
Crystal system:
hexagonal
Mohs hardness:
5 (reference stone)
Specific gravity:
3.16-3.22
Refractive index:
birefringent 1.630-1.667
Max. Birefringence:
0.002-0.008
Dispersion:
weak 0.013
Pleochroism:
weak to strong, strongest in blue Apatite (blue/colourless)
Luminiscence:
very variable
Lustre:
vitreous
Cleavage:
indistinct
Fracture:
conchoidal
Colour:
colourless, yellow, green, pink, blue, purple, brown