Silver, Pyrargyrite

This specimen of massive pyrargyrite comes from the Waterloo No. 3 Mine in British Columbia. Pyrargyrite is a silver antimony sulfosalt mineral and an important ore of silver, commonly known as "ruby silver" due to its deep red colour in fresh crystals. It is isostructural with proustite (a silver arsenic sulfosalt), although the two differ in chemical composition.

Pyrargyrite is commonly found in silver-bearing hydrothermal veins, and its name—derived from Greek—refers to both its silver content and fiery red colour. At the Waterloo No. 3 Mine, the mineral occurs as massive vein material. While pyrargyrite is typically a deep red, it darkens rapidly upon exposure to light and air, making freshly mined material noticeably dark.

This particular vein is composed almost entirely of pyrargyrite. In areas where calcite has been leached out, native silver can be seen exposed within the matrix—indicating the high silver content of the material. Under the microscope, fine black acanthite needles are visible in spots, representing a later-stage “cabinet growth” over the pyrargyrite. This material was collected and identified by Dave Van Dieren, a respected and experienced field collector based in British Columbia.