Verdelite
Variety Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
Also called Green tourmaline
About it
Green tourmaline, the commonest gem colour, coloured mainly by iron. Crystals often look nearly black down their length; Brazil, Namibia, Afghanistan, and Maine are sources.
- Type
- Variety
- Group
- Elbaite variety (tourmaline)
- Formula
- Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
- Hardness (Mohs)
- 7–7.5
- Specific gravity
- 3–3.26
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Trigonal
- Colours
- green, yellow-green, bluish green
- Transparency
- transparent, translucent
- Cleavage and fracture
- poor; uneven to conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.