aPATITE

Photo courtesy of Wikipedia

Species:  Apatite
​​Mohs Hardness:  5 out of 10
Color:  Colorless, pink, green, blue, violet, yellow
RI:  1.634 to 1.638 (+0.012 / -0.006)
Birefringence:  0.002 to 0.008
SR/DR/AGG:  DR
Clarity Type:  Type II
Pleochroism:  Uniaxial negative (distorted optic figure possible, may appear biaxial)
Spectrum:  Not diagnostic
Fluorescence:  Not diagnostic
SG:  3.18 (+/- 0.05)

apatite Facts

Apatite occurs in various colors, including colorless.

Some of the most prized apatites have vivid neon blue hues that resemble Paraiba tourmaline.