Realgar on calcite I have visited this lovely mineral that is also known as ruby sulphur before (see
Realgar on calciteI have visited this lovely mineral that is also known as ruby sulphur before (see http://on.fb.me/1dC9ZWZ and http://on.fb.me/1dC9ZWZ), but this specimen was so wonderful that I couldn’t resist sharing this lovely Chinese chunknestling on calcite. A sulphide of arsenic, it shouldn’t be licked, and hands should be washed after handling. In addition it disintegrates with prolonged exposure to light, which slowly disaggregates its crystal structure, so prize specimens should always be stored in the dark when not being drooled over. It forms from low temperature mineral charged fluids, precipitated into hydrothermal veins, at hot springs or geysers and from steamy vapours in volcanic fumaroles. It is a bright and visible sign of sulphide mineralisation beloved by prospectors. This sample sits on a double terminated calcite, with a little sea urchin spray of picropharmacolite, an alteration product formed when arsenic sulphides are oxidised. sadly I can’t trace a scale.LozImage credit: Exceptional Minerals -- source link
#geology#mineral#crystal#realgar#calcite#sulfur#arsenic#chemistry#fluid#mineralogy