Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
monocliniccommonSulfides
Acanthite
Ag2S
This specimen features dark, metallic, blocky to dendritic crystals of acanthite, intimately intergrown with bright, wire-like native silver.
Acanthite Physical Properties
Mohs Hardness
2Crystal System
monoclinicLuster
metallicStreak Color
dark gray to blackCleavage
indistinct/poor on {011}Fracture
conchoidalSpecific Gravity
7.2Colors
lead-gray, dark gray, blackTransparency
opaqueType Locality
Kongsberg, Buskerud, NorwayMineral Group
SulfidesUses
silver ore, collectorAssociated Minerals
native silver, galena, sphalerite, chalcopyrite, pyrite, quartz, calciteRarity
commonGeological Context
Acanthite is a low-temperature polymorph of argentite, forming in hydrothermal veins and often found in silver-rich ore deposits. It is the stable form of silver sulfide below 173°C.
