Miargyrite

specimen number:
2273025

location:
Kelly Mine, San Bernardino Co., California, USA

description:
Bright lustrous metallic micro crystals of miargyrite quite rich across the top of matrix. This is very good for the species and locality. The specimen comes with several previous labels as shown at the end of the video.

The Kelly mine, located at Red Mountain within the Randsburg district of San Bernardino County, California, is a historic silver operation known for its extraordinarily rich high-grade silver deposits. Geologically, the deposit is a low-sulfidation epithermal vein system hosted within the Precambrian Rand Schist, where structural faulting and fracturing facilitated the deposition of rich silver-bearing quartz veins. The mine was discovered accidentally in 1919 during a local lull in the area's older gold and tungsten booms, quickly triggering an intense silver rush. Under the California Rand Silver Mining Company, the underground operation expanded into one of the most productive silver mines in the United States during the 1920s, featuring numerous shafts and extensive subterranean levels. Commercial production of high-grade shipping ore peaked through the mid-1920s and then operated intermittently until large-scale underground mining ceased around World War II.

Miargyrite is a relatively uncommon silver antimony sulfide mineral that crystallizes in the monoclinic system and typically serves as a minor ore of silver. Geologically, it forms in low-to-medium temperature hydrothermal veins, often developing during the late stages of mineralization alongside other sulfosalts, acanthite, and native silver in a quartz matrix. The mineral is characteristically iron-black to steel-gray with a metallic luster, though thin fragments can show deep cherry-red internal reflections under intense light. Its most distinctive field indicator is a characteristic cherry-red streak, which sets it apart from other visually similar dark silver sulfides. At the Kelly mine, miargyrite occurred in notable abundance, forming distinct massive veins and occasional complex crystal clusters embedded within the siliceous ore.

Questions about this specimen?
Send an email or call us: 314-341-1811.