Crocidolite (blue asbestos), variety of <a href="https://en.wikipedia.org/wiki/Riebeckite" class="extiw" title="en:Riebeckite">Riebeckite</a> - Locality: Pomfret Mine, Vryburg - Exposed in the Mineralogical Museum, Bonn, Germany
<a href="//commons.wikimedia.org/wiki/User:Raymond" title="User:Raymond">Raimond Spekking</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>