Pedrazzini to the Egleston Collection at the Columbia School of Mines, where there are also a number of other specimens of polybasite and stephanite, as well as a remarkable specimen representing the transition of an argentite crystal into cerargyrite and a fine
embolite. The American Museum of National History in New York also has, from this mine (the Las Chispas), what is probably the largest mass of polybasite crystals ever taken out in one piece.