Walstromite with Unknown Blue, Big Creek – Rush Creek Deposit, Fresno County, California, USA.
Walstromite is pretty much limited to a few locations in the foothills of the Sierra Nevada mountain range in California. Here’s a very nice, and relatively large, specimen from the Big Creek – Rush Creek Deposit, Esquire #5 mine. The orangish walstromite glows best in midwave, but also nicely in shortwave; the unknown blue glows in all wavelengths. There's been much debate regarding the blue, and it's typically mis-id'd as celsian. However, preliminary testing reveals it is more likely a barium carbonate, and potentially witherite. More testing is forthcoming. The rock also holds tiny blue grains of Bazirite and small grains of green yellow fluorescing Fresnoite. This specimen is about six by five inches and weighs in at 1500 grams (exactly).
Shown in midwave, shortwave, longwave and natural.