Hydroxylapatite
Mineral Ca5(PO4)3(OH)
Also called Hydroxyapatite
About it
The apatite of bone and tooth enamel; as distinct crystals it is much rarer than fluorapatite and needs analysis to name for sure. Found in some talc schists, pegmatites, and cave deposits.
- Type
- Mineral
- Group
- Phosphate, apatite group
- Formula
- Ca5(PO4)3(OH)
- Hardness (Mohs)
- 5
- Specific gravity
- 3.1–3.2
- Streak
- white
- Lustre
- vitreous (glassy), resinous
- Crystal system
- Hexagonal
- Colours
- white, grey, yellow, green, brown, colourless
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- poor basal; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.