Microcrystalline gypsum

A rock of only micro chalk crystals


This image shows extremely small gypsum crystals, visible only under the microscope: to the naked eye, this rock appears white and opaque.


This particular sample was collected near the Dibona Hut and dates back to the upper Triassic  (approximately 230 million years ago).


Gypsum is an unusual rock, and it is formed in very particular environments: it derives from the evaporation of sea water in an extremely hot and dry climate.


This can only happen in tropical latitudes, in environments close to the sea similar to salinas, 


and in extremely dry climates such as, for example, the shores of the Persian Gulf close to Abu Dhabi.


Approximately 230 million years ago, the Dolomites would have been a coastal plain, at tropical latitudes and subject to an almost desert climate.


If you want to get an idea of what that looked like, watch satellite images.In the sabkha of Abu Dhabi, gypsum is forming beneath a layer of dark mucilage that is clearly visible on satellite images.





Name: Microcrystalline Gypsum
Classification: Chemical sedimentary rock, evaporite
Mineral composition: Gypsum
Fossils: None
Location: Dibona Refuse(46°32’5.09″N 12°4’21.20″E)
Formation: Travenanzes formation
Era: Upper Carnian (approximately 230 million years ago)
Depositional environment: Sabkha