Sphalerite and Dolomite with Chalcopyrite on Brecciated Chert, Swalley Mine, Tri-State District, Baxter Springs, KS, Dr. David London Collection L-232, Medium Cabinet 8 x 11 x 11 cm, $2,500. Online Feb. 27.
NSMW13619
An extraordinarily large sphalerite crystal to 10+ cm across showing classic polysynthetic twinning. This is the largest sphalerite crystal I have ever seen. Museum caliber specimen in excellent condition. An important Tri-State specimen. Mine attribution per Dan Weinrich.