Rock gypsum
Rock
Also called Gypsum rock and Gypsite
About it
Massive, granular evaporite rock of gypsum, soft enough to scratch with a fingernail and not fizzing in acid. Mined for drywall and plaster in Nova Scotia and Ontario; the fine-grained kind, alabaster, is carved.
- Type
- Rock (sedimentary)
- Group
- Sedimentary (evaporite)
- Hardness (Mohs)
- 1.5–2
- Specific gravity
- 2.2–2.4
- Lustre
- vitreous (glassy), silky, dull
- Colours
- white, grey, pink, tan, colourless
- Transparency
- translucent, opaque
- Cleavage and fracture
- granular; single crystals have perfect cleavage
Typical values: real specimens vary. For more, see mindat.org.