Apatite (hexagonal) Ca5[(F,Cl,OH)/(PO4)3]

Apatite 1P
 Colour: colourless
Pleochroism: non pleochroic
Habit: tabular, prismatic crystals
Relief: positive
Cleavage, fracture: none
Apatite PX
 Isotropic or anisotropic: anisotropic
Extinction: straight
Interference colours: 1st order

Collophane (amorphous) Ca5[(F,Cl,OH)/(PO4)3] x nH2O

Collophane 1P
 Colour: brown, yellow, colourless
Pleochroism: non pleochroic
Habit: amorphous
Relief: positive
Cleavage, fracture: none
Collophane PX
 Isotropic. Therefore it doesn't prove crossed polarised light properties.
Last modified: Monday, 3 April 2017, 10:51 AM