Proustite

A Red Silver Treasure

- BOB JONES

Today, proustite, a red silver compound, is hard to find. While native gold is rarely found as a compound, silver, on the other hand, forms a variety of wonderful compounds that collectors treasure: waxy-looking chlorargyrite, dark gray to black acanthite, stephanite, polybasite and two sulfosalts, pyrargyrite and proustite.

The red color of these last two silver minerals makes them the most appealing and eagerly sought silver species. Collectors are overjoyed when they obtain a specimen of either of these silver compounds, since today's silver mines rarely encounter such specimens. Many found in the early centuries of silver mining have long since ended up in museums or in private collections.

This choice specimen of proustite shows signs of darkening, but is a fine red, from Freiberg, Saxony, Germany.

Collector's Edge

Pyrargyrite is a silver antimony sulfide, and proustite is a silver arsenic sulfide. Both exhibit a lovely red color, with proustite being the brighter red, hence the general name ruby silver. Both species are rare, with pyrargyrite a little more common.

Of the two, proustite exhibits the richest red color, and when found in quantity in Chanarcillo, Chile, it was given the name Sangre de Torro, or “Blood of the Bull.” Pyrargyrite is a somewhat darker red color and is still occasionally found in silver mines of Mexico.

RED SILVER “SWEETENER”

Some 30 years ago, I was traveling in Mexico visiting silver mines with my son, Evan, and Bill Panczner and his son, Chris. This included a visit to a silver mine at Fresnillo, Chihuahua, Mexico.