Gillespite
Mineral BaFeSi4O10
About it
Deep red, square micaceous plates of barium-iron silicate, rare and striking; from the Alaska Range, Mariposa County in California, and the Yukon.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), gillespite group
- Formula
- BaFeSi4O10
- Hardness (Mohs)
- 3–4
- Specific gravity
- 3.39–3.4
- Streak
- pink
- Lustre
- vitreous (glassy)
- Crystal system
- Tetragonal
- Colours
- deep red, rose red
- Transparency
- transparent, translucent
- Cleavage and fracture
- very good basal
Typical values: real specimens vary. For more, see mindat.org.