JRB01 Ferberite with Jeromite on Quartz
Kami Mine, Ayopaya Prov., Cochabamba Dept., Bolivia
9.4x 9.1x 7.5 cm
$3600
A beautiful specimen with a group of lustrous black ferberite crystals (the largest a twin) with a contrasting medley of arsenic bearing minerals- jeromite, 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.