Description | This sample, 10 cm across, contains radiating needles of stibnite in a fine grained stibnite matrix. Stibnite, Sb2S3 (antimony sulfide), is a silvery gray mineral with a metallic luster. When it crystallizes as clusters of gray needles, it is fairly easy to identify. When fine grained and massive it looks like many other gray minerals. It is commonly deposited by alkaline waters and occurs in association with quartz, calcite, sulfides of the base metals, arsenic, gold, and silver. |