Rock gypsum
This rock normally occurs as massive gypsum (hydrated calcium sulfate).
TEXTURE This coarse- to fine-grained rock has a fibrous habit. It may also show bedding, which is often strongly distorted. Rock gypsum is usually interbedded with sandstones, marls, and limestones. A soft rock, it can be scratched easily with a fingernail.
ORIGIN Forms in evaporite rock sequences in association with dolomite rock and marl and the minerals anhydrite, halite, and calcite.
Grain size: Coarse to fine
Classification: Chemical
Fossils: None
Grain shape: –
