Data about the Desert rose:

Chemical formula CaSO4 * 2H2O
Mineral class sulfates
Crystal system monoclinical
Hardness 1.5 to 2
Density 2.3 g/cm3 to 2.4 g/cm3
Color red-brown
Line color white
Gloss glass gloss
Break unevenly
Fissileness perfectly

That's what you get when you show a rock to a geologist.