Calcium Phosphate
Ca5(PO4)3(F,Cl,OH)
Chemical name
Calcium Phosphate
Mineral name
Apatite
Chemical formula
Ca5(PO4)3(F,Cl,OH)
Crystal system
hexagonal
Crystal Class
hexagonal-dipyramidal (6/m)
Space Group
P6_3/m
Unit cell
a [Å]:9.38
b [Å]:9.38
c [Å]:6.86
Molecular weight [g/mol]
689,67
Formula units
Z=2
Frequent crystal surfaces
{10-10}, {0001}, {10-11}
Mohs hardness
5
Density [g/cm3]
3.2
Cleavage
indistinct
Fracture / Tenacity
brittle to conchoidal
Color
usually green, colorless, yellow, blue, violet, pink, brown
Streak
white
Transparency
transparent to translucent
Optical character
uniaxial (-)
Refractive Index
nω=1.631-1.675; nε=1.627-1.668
Birefringence δ
0.004 - 0.014
Pleochroism δ
weak to very weak