Precious Opal: 

Mississippi's First Gemstone

James E. Starnes, Geologist

MDEQ Office Of Geology

The State of Mississippi has certainly been endowed with extremely rich fossil deposits dispersed throughout much of the exposed geological section.  Many of Mississippi’s very unique geological treasures adorn local personal collections and professional collections in museums as far away as Japan.  Though the interest in Mississippi’s geology by collectors and scientists is mainly in excellently preserved fossil specimens, many coarse-grained, aggregate-bearing deposits such as the Citronelle and Pre-loess gravels are regularly combed for semi-precious stones such as agate, carnelian, jasper, clear quartz, and fossil palm.  Until recently, no precious stones have been reported from Mississippi.

In neighboring Louisiana, small-scale mining of gem-quality opal has been done in the basal Fleming Formation (Catahoula Formation equivalent in Mississippi) of Vernon Parish, Louisiana, near the Texas border for over a hundred years.  The vibrantly colored opal cements coarse-grained sand into hard sandstone and quartzite which were fashioned into gemstones and once sold to Tiffany’s of New York.  Much of the Louisiana gem-quality Opal on the market today can be credited to Ben F. Stevens, whose mine is closed at present.  (Louisiana Opal-The One That Dares To Be Different by Ben F. Stevens, 1999)

Recent detailed geological mapping of the Catahoula Formation in Claiborne County by the Office of Geology’s (Mississippi State Geological Survey) Surface Geology Division under a United States Geological Survey (USGS) Statemap Grant led to the discovery of another precious opal deposit much like the Louisiana locality.  The material was first tested for gem quality by the Mississippi Gem and Mineral Society’s artisans, Janie Hand and Joy Rushing.  The exquisitely crafted stones show brilliant flashes of fire, ranging in color from green to red.

A 7.5 min geological map of the area was published by the Office.  Though, no specific details on the location of the outcrop are being divulged to protect it from being raided before it can be completely studied by scientists.  The site is sensitive, not only because of the presence of precious opal it contains, but pre-historic artifacts have also been found in association with the site.   These artifacts include pottery, artifacts made from local chert gravel, and artifacts of Catahoula quartzite (of which some are opalescent).

Because of the amount of volcanic ash that was deposited in the Catahoula Formation, a number of quartzite bearing exposures can be found along its outcrop belt in Mississippi. Therefore, it is possible that other exposures of the Catahoula Formation, as well as, other quartzite bearing Formations in Mississippi may also contain precious opal deposits that have yet to be discovered.

For more information about the geology of Mississippi call us at (601) 961-5500 or e-mail:

www.deq.state.ms.us