Tourmalinated quartz
Variety SiO2
Also called Tourmaline quartz
About it
Clear to milky quartz crossed by black needles of schorl tourmaline, thicker and more opaque than rutile needles. Mainly from Brazil and Madagascar.
- Type
- Variety
- Group
- Quartz variety
- Formula
- SiO2
- Hardness (Mohs)
- 7
- Specific gravity
- 2.65–2.66
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Trigonal
- Colours
- colourless or milky with black needles
- Transparency
- transparent, translucent
- Cleavage and fracture
- none; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.