Elbaite
Mineral Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
About it
The lithium tourmaline behind most gem colours, often zoned pink inside green as "watermelon"; striated prisms from Brazil, Afghanistan, Madagascar, and the Pala district of California.
- Type
- Mineral
- Group
- Silicate (cyclosilicate), tourmaline group
- Formula
- Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
- Hardness (Mohs)
- 7–7.5
- Specific gravity
- 2.9–3.1
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Trigonal
- Colours
- pink, red, green, blue, yellow, colourless, multicoloured
- Transparency
- transparent, translucent
- Cleavage and fracture
- indistinct; uneven to conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.