u/Immediateswitchblade

Vesuvianite find from the Traverse Creek special interest area in El Dorado County, CA. I found it growing on a boulder hiding halfway under a bush. Samples like this have been historically mined at this locality and sold to Tiffany’s as “California Emeralds.”

Unlike genuine beryl emeralds or many of the finds further east in the Sierras, these minerals do not form from pegmatites, but rather metamorphic rock. The bedrock of the Stifle Claim locality is overwhelmingly serpentinite, formed from metamorphosed mafic and ultramafic rock.

The serpentinite here contains a range of interesting serpentine minerals such as antigorite, chrysotile, and tremolite (with alleged nephrite jade being found here as well). However, the vesuvianite to my knowledge is not found in serpentinite.

The matrix the vesuvianite crystals are found in is what I’ve identified be rodingite. This rock forms white veins and dikes that cut through the host serpentinite. It is a dense white rock that stands out against the green/blue serpentinite and can be found readily in many of the tailings piles throughout the locality.

Although much of the rodingite found here is very tough and difficult to break with a hammer, the regions where it forms mineral rich vugs tend to be much more brittle and crumbly in texture. Other minerals I’ve found in such vugs I’ve identified as clinochlore and grossular, although only in near microscopic druzy deposits.

This mineral being vesuvianite has been confirmed by multiple local collectors who have been prospecting this locality for far longer than I have; many of whom have back when it was a private claim from the local mineral society. Many have told me this is the most vibrant green vesuvianite they’ve ever seen come from traverse creek.

The geology of this locality is incredibly rich and complex. If you’re planning a visit, be sure to check out the mindat page beforehand. Also be sure to be mindful of sensitive native plant species in the area while prospecting.