
1) Arsenic mineral 2) Copper mineral 3) Trigonal mineral
Found on
https://www.crosswordclues.com/clue/aktashite

Aktashite is a rare arsenic sulfosalt mineral with formula Cu6Hg3As4S12. It is a copper mercury-bearing sulfosalt and is the only sulfosalt mineral with essential Cu and Hg yet known. It is of hydrothermal origin. It was published without approval of the IMA/CNMNC. ...
Found on
http://en.wikipedia.org/wiki/Aktashite
No exact match found.