February 22, 2005
State Survey Reports on Large Opal Deposit
On March 4, 2005, the Wyoming State Geological Survey (WSGS) will release a new report on a large opal deposit recently discovered in Fremont County, central Wyoming. Open File Report 05-1, entitled Geology of the Cedar Rim opal deposit, Granite Mountains, central Wyoming, by W. Dan Hausel and Wayne M. Sutherland, is a 12-page report containing a location map and photographs of the opal. The report will be released to the public at the WSGS sales office on the University of Wyoming campus in Laramie at 11:00 am on Friday, March 4. Due to interest in the deposit by a group of companies and individuals, customers must be present at the sales office to receive the report at 11:00 am. After this date, copies of the report can be ordered by phone.
Geologists with the Metals and Precious Stones Section at the WSGS have been investigating this gemstone deposit for the past two field seasons following up on a tip by a local rock hound. Work by Hausel and co-author Sutherland indicates that the deposit is dominated by giant resources of common opal, with some significant fire opal, but only traces of precious opal.
Numerous opals were collected by the WSGS including three opals that weighed 25,850 carats (11.4 pounds), 57,100 carats (25.18 pounds), and 77,100 carats (34 pounds), respectively! The latter specimen is on display at the WSGS building in Laramie. According to the report, only a very small part of this large, extensive deposit has been examined to date, and additional work and/or company exploration on this deposit could potentially lead to the discovery of some hidden seams of precious opal.
from the Office of the Wyoming State Geologist
Ron Surdam, State Geologist