Apatite
| Colour | Blue, Green, Clear, Yellow |
|---|---|
| Mohs hardness | 5 (defining mineral) |
| Lustre | Vitreous to subresinous |
| Streak | White |
| Crystal system | Hexagonal |
| Transparency | Transparent to translucent |
| Cleavage | [0001] indistinct, [1010] indistinct |
| Fracture | Conchoidal to uneven |
| Chemical formula | Ca 5 (PO 4 ) 3 (F,Cl,OH) |
| Specific gravity | 3.16–3.22 |
What is Apatite?
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ion, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca10(PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6F2 and Ca10(PO4)6Cl2.
How to identify Apatite
- Lustre: Vitreous to subresinous.
- Hardness: Mohs 5 (defining mineral) — soft; a knife will scratch it.
- Streak: White.
- Habit: Hexagonal crystal system.
Apatite in different forms
Stones often confused with Apatite
Frequently asked questions
How hard is Apatite?
Apatite is Mohs 5 (defining mineral) on the hardness scale.
What colour is Apatite?
Apatite is typically blue, green, clear, yellow (Transparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown).