Kesterite with Mushistonite on Muscovite
Pingwu beryl mine, Huya township, Mt Xuebaoding, Sichuan, China
Small Cabinet, 7.7 x 6.8 x 5.4 cm
Ex. Dr. Stephen Smale

The tungsten mines on the mountain of Xuebaoding have given us some big surprises over the years. In the late 1990's, a new species was thought to have been found here, tentatively called Pandaite. However, this turned out instead to be a coating of the blue crusty mineral mushistonite atop sharp textbook crystals of the rare species Kesterite that were simply 1000 times better than any previously known, and so mistaken as something new! Superb combinations of the rare species Kesterite (a Cu-Zn-Fe-Sn sulfosalt) and the coating of bluish Mushistonite (a Cu-Zn-Fe-Sn hydroxide) do not often achieve the level of aesthetics that this small cabinet piece has, as an aesthetic specimen worthy of any collection. The sharp, complex Kesterites, which reach up to 1 cm, are clustered perfectly right in the middle of the Muscovite matrix, and they are richly coated with mint-green Mushistonite. The few windows through the Mushistonite coating reveal the excellent, metallic luster of the Kesterite. This is one of the best of these combos that I have seen in any size. See the article on Xuebaoding in The Mineralogical Record, V. 36, #1, Pp. 45-57. ex Dr. Steve Smale collection.