Selenite crystals, a variety of the mineral gypsum (calcium sulfate dihydrate: CaSO<sub>4</sub>·2H<sub>2</sub>O). Max crystals length 8 cm, color due to impurities.
<a href="//commons.wikimedia.org/wiki/User:Khruner" title="User:Khruner">Khruner</a>
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