Mineral Specimen #6789 Sanbornite
Big Creek, Fresno Co., California
21 x 7 x 4.5 cm
8.3 x 2.8 x 1.8 in
Ex. Steve Pullman, Ex. California Academy of Sciences
Ba2(Si4O10) and BaFe2+[Si4O10]
A relatively large specimen of Snaborninte which is for the most part white in color with a prealy, directional luster. There are other, dark colored materials present as included blebs. Some of these are black in color and some are reddish brown. There is also quite a bit of reddish brown staining in the Sanbornite. The reddish brown could be Traksite. Interestingly, the white areas of Sanborninte fluoresces a yellowish white under UV (stronger and more yellow under LW than SW). There is a specimen from the location, that has similar fluoresence, posted on mindat with a suggestion ot could be Opal pseudomorphed after Sanbornite still retaining the perfect cleavage and pearly luster. There is a further suggestion for the specimen that this could be the unidentifed mineral 21 described by Bob Walstrom. The last photo was taken under LW.
Flaws: Essentially massive material with the largest two surfaces composed of cleavage surfaces.
This mineral is also found in the following galleries: Minerals From California and Nevada | Phyllosilicates | Rare Minerals | Fluorescents | Minerals Priced Between 50 and 99 Dollars