Euhedral, hexagonal molybdenite on quartz, from Molly Hill mine, Quebec, Canada. The large crystal is 15mm across (corner to corner).
John Chapman (<a href="//commons.wikimedia.org/wiki/User:Pyrope" title="User:Pyrope">Pyrope</a>)
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>