Franckeite on matrix (!)Franckeite is a relatively rare iron, lead, tin, antimony sulfosalt, which is not often found in well crystallized display specimens, especially on matrix! This is one of the very few specimens of Franckeite that I have seen from the famous Siglo XX mine, and certainly one of the most eye catching. This piece hosts several groups of Franckeite consisting of somewhat "sword" shaped crystals forming spherical aggregates which are sitting on minor

black cyclic twinned crystals which are associated with unique and very rarely seen prismatic Quartz crystals (measuring up to 2

which sometimes played host to beautiful jet-black Ferberite crystals

This remarkably attractive specimen features beautiful lustrous

combined with the bright luster

the word copal is used to describe a hardened resinous substance which is found in an intermediate stage of hardening and polymerization between softer / "gummier" resins and amber

To the credit of Alfredo Petrov and Dr

and dramatically aesthetic matrix piece

Specimen # ANDIT4114

and the fact that there are THREE DISTINCT TWINS together

the Brookites feature the same classic black "phantoms" that are so desirable in specimens from the European Alps

Specimen # BOL711B05

and this piece would make a fine addition to any thumbnail collection or a suite of Pakistani minerals or worldwide metamorphic minerals