Rhodochrosite from Sweet Home Mine, Colorado USA - A Brief History

Rhodochrosites (3.36-5.22ct) from the new Detroit City portal, at Sweet Home Mine in Colorado

We are excited to now be able to offer beautiful faceted Rhodochrosite from the long closed Sweet Home Mine in Alma, Colorado, USA.

The Sweet Home mine was initially established in 1873 high in the Rocky mountains, as a silver mine. It is located on the southern slope of Mt. Bross, northwest of the small mountain town of Alma. As a silver mine it was not especially profitable and ownership changed many times and it was worked only sporadically until the 1990’s. It had occasionally produced fabulous crystal specimens of cherry red Rhodochrosite, arguably the most famous being the ‘Alma Queen’ and ‘Alma King’ specimens.

In 1991 it was leased to a group with the sole goal of mining it specifically for Rhodochrosite specimens, using modern extraction and specimen preparation techniques. As a specimen mine it was extremely successful, producing many fabulous specimens. The broken crystals that were cut as gems became well known as the standard for gem Rhodochrosite. The mine was unfortunately closed in 2004 and the portal was sealed shut.

For the next 12 years planning and additional exploration were done and in 2016 a new portal was begun 60 meters above the original entrance, with the goal of tapping the same vein system. This new portal is call the Detroit City adit, after the name of the original block of mining claims. Mining began in 2016 and first involved a 140 meter adit to reach the vein system. This was achieved in 2018 and the first few Rhodochrosite pockets were found as they followed the vein an additional 70 meters. In 2019 the vein was mined upwards intensively and several pockets were found producing more of the world class Sweet Home Rhodochrosites for the first time since 2004.

Sweet Home Mine Crew, ca 1922. Credit: Mineralogical Record, July-August 1998 Vol. 29 No. 4 (Photographer Unknown)

In late 2020 the first gems were cut from the 2018-2020 mining. We have recently acquired some of the special stones from this new production, and are excited to be able to offer them for the first time since the mine closed in 2004.

If you are interested in these Rhodochrosite gems, or have additional information to share regarding this interesting material and mine, we would love to hear from you.

Full image credit to the Mineralogical Record 1998 Vol 29 No.4 for the photograph of the miners included.