Montebrasite
Mineral LiAl(PO4)(OH)
About it
The hydroxyl partner of amblygonite and much the commoner of the two, in white cleavable masses in lithium pegmatites. Clear yellow gem crystals come from Minas Gerais in Brazil; named for Montebras in France.
- Type
- Mineral
- Group
- Phosphate, amblygonite group
- Formula
- LiAl(PO4)(OH)
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 2.95–3.05
- Streak
- white
- Lustre
- vitreous (glassy), pearly, greasy
- Crystal system
- Triclinic
- Colours
- white, cream, pale yellow, colourless, pale green, lilac
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction, good in another; uneven fracture
Typical values: real specimens vary. For more, see mindat.org.