JRB06 Ferberite, Jeromite with Quartz
Kami Mine, Ayopaya Prov., Cochabamba Dept., Bolivia
11.5x 7.6x 6.5 cm
$400
A nice specimen of lustrous black ferberite with a coating of contrasting bright orange jeromite and orpiment on quartz. The "jeromite" is not actually a mineral-- it is an arsenic, selenium, sulfur glass that lacks a definite crystal structure (hence the "glass" term) best known from this mine. In the past, I saw small single quartz crystals coated with this orange-red material, but this discovery is the first time that I have seen such rich examples. Not perfect, but quite colorful.