Gypsum is made of calcium sulfate and can be found in 4 different variants: desert rose, selenite, gypsum flower and alabaster.
Desert rose is a combination of mineral gypsum and sandgrains. The sandgrains are integrated into the crystal structure of gypsum (some times baryte). Desert rose cannot be classified as a mineral or stone, although the latter is mostly the case. Desert rose is formed when water with gypsum or baryte dissolved in it, evaporates (mainly in desert areas). The sandgrains that are present will stick on the plane around the c-axis of the crystal.
Selenite usually forms thin crystals and gets its colour from contaminations like other minerals.Top
Chemical & Physical Information
|Chemical Name||Calcium Sulfate Dihydrate|
|Molar mass||172.17 g·mol-1|
|Crystal habit||Sandy dull, clay like structure|
|Cleavage||Perfect , vague  and |
|Colour||Colourless, white, brown, green or combinations.|
|Opacity||Transparent to translucent.|
|Extra||Abundant with many applications.|
 Specimen from my personal collection, photo taken by me.