mineral

Likely gypsum (selenite/alabaster)

Gypsum, CaSO₄·2H₂O

AI-generated identification · may be incorrect

White to translucent, vitreous-to-silky luster with visible cleavage surfaces; gypsum is monoclinic and very soft (Mohs 2), easily scratched by a fingernail. The photo alone cannot confirm the identification; calcite is another possibility.

Identified October 5, 2026More mineral →

Explore Likely gypsum (selenite/alabaster) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Gypsum forms when calcium-sulfate-rich water evaporates in sedimentary basins, or through hydration of anhydrite. It occurs in rocks of many ages; the specimen’s age cannot be determined visually.

Uses & applications

Used to make plaster, drywall, and cement; clear selenite and attractive gypsum pieces are collected, though this rough fragment has little gem value.

Geological facts

Gypsum has perfect cleavage and can split into thin sheets; its softness is a useful field test.

Field identification & locations

The pale, blocky, cleaved appearance is consistent with gypsum. Check whether it is scratched by a fingernail and whether it fails to fizz in dilute acid (unlike calcite). Gypsum is plausible in the arid sedimentary regions near the reported location, but the photo cannot establish provenance.