Gypsum var. selenite from Andamooka Ranges - Lake Torrens area, South Australia.
<a href="//commons.wikimedia.org/wiki/User:JJ_Harrison" title="User:JJ Harrison">JJ Harrison</a> (<a rel="nofollow" class="external free" href="https://www.jjharrison.com.au/">https://www.jjharrison.com.au/</a>)
CC BY-SA 2.5
Own work, specimen from the Willems Miner Collection