Colorado Mineral Society Patch

American Federation of
Mineralogical Societies

Rocky Mountain Federation of Mineralogical Societies

A Visitor’s Guide to Colorado Gemstones Article

On International Gem Society's
Website mentions the
Colorado Mineral Society

Click here to read

Some links Require Acrobat Reader (it's free)

Unique Visitors

Thanks for stopping by!

Counter courtesy Web Counter

Welcome to the Colorado Mineral Society

Celebrating our 82nd Year!
1936 - 2018

Next CMS Monthly Meeting
Friday, March 2nd, 2018 at 7:30 pm
St. Paul Episcopal Church
9200 W. 10th Ave, Lakewood, CO
(10th Avenue and Garrison Street)


March's Topic:

The Sweet Home Mine-from Silver to Rhodochrosite

Rhodochrosite from Sweet Home Mind

Dr. Karen Wenrich
Dr. Karen Wenrich will be speaking about the geology, geochemistry, and historic and recent mining history of the famous Sweet Home Mine, near Alma, Colorado.

The Sweet Home Mine Pb-Ag mining began in 1872--the mine holds U.S. Patent #106--one of the 1872 Mining Law's oldest. Based solely on its unimpressive silver output, the Sweet Home should have faded into obscurity and abandonment a century ago. However, the tenacity of miners allowed it to operate intermittently for over 120 years. The last silver mining occurred in 1966. During the 120 years many museum quality cherry-red rhodochrosite rhombs in association with quartz, fluorite, and multiple sulfides were removed, and some sold as far away as to the Harvard Museum around 1900. Far more money has been made from Sweet Home rhodochrosite than was ever made from silver ore.

In 1991, Sweet Home Rhodo, Inc (Bryan Lees and others) reopened the mine and operated it as a specimen mine until 2004 when it was cemented closed. During that time what are widely acknowledged at the world’s finest rhodochrosite specimens were collected; including the Alma King and the “Denver Wall of Rhodochrosite” a reconstructed plate of 1-2 inch rhodochrosite rhombs on quartz that is on exhibit at the Denver Museum of Nature and Science. Although a number of researchers had studied the chemistry of the hydrothermal fluids responsible for formation of the vein orebody and associated gangue minerals, Bryan Lees reached out to Dr. Karen Wenrich in 1994, and asked her to conduct a geochemical investigation to determine the conditions associated with the rhodochrosite mineralization. Dr. Wenrich’s talk will review what was learned at the Sweet Home Mine, findings that along with detailed new geologic mapping at the mine led Bryan Lees to reopen the mine in 1991 in the hopes of finding additional pockets of world class rhodochrosite specimens, and what might be the inspiration for opening the new mine, the Detroit City Mine, in 2017.

Visitors, guests and kids are always welcome
to attend the general meetings.

Click here for map

CMS Members Jeff Self and Donna Ware featured on Colorado Public Radio's “Colorado Matters”

CMS members Jeff Self and Donna Ware were featured in an interview on the “Colorado Matters” program on Colorado Public Radio. The recorded interview with Ryan Warner can be listened to online via the CPR website at the link below, along with a story and photos about them.

Click Here for Interview

Entire site contents © 2018 Colorado Mineral Society, a Colorado non-profit, educational organization