Anhydrite
Hydrogenous sedimentary rock.
Anhydrite is an evaporite mineral composed of calcium sulfate (CaSO4). When exposed to water it will convert to gypsum (CaSO4 nH20). This sample displays white layers of anhydrite separated by organic rich layer. These are probably seasonal cycles: the dark, probably during winter wet season), and white layer (summer dry season). This sample is from Castile Formation, Permian Basin near Carlsbad, New Mexico. The Castile Formation is nearly 2,000 feet thick in the Delaware Basin of West Texas. |
| https://gotbooks.miracosta.edu/rocks/sedimentary/2.html |
2/2/2021 |
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