Stage 4 is marked by a mineral assemblage composed of quartz + antimony-lead-silver sulfosalt minerals (Figure 4(r)) that prevailingly include boulangerite and jamesonite, as well as minor bournonite, tetrahedrite, and andorite
. This stage hosts the majority of the Sb and Ag mineralization and yields the ores with relatively high average Ag grades.
The place in question is an entirely landlocked, mountainous, somewhat mysterious-seeming country which boasts a long mining history and has a secure reputation for turning out world-class specimens of--oh, let's see--metallic species (andorite
, pyrarygrite, stannite, franckeite, cylindrite), other primary ores (cassiterite, ferberite), and glamorous phosphates (phosphophyl-lite, paravauxite, vivianite, ludlamite) such as we have long admired and lusted after.
In addition, andorite
is another Ag- and Sb-bearing mineral but is rarely found in the Keyue orefield; we can only find the stumpy andorite
distributed in freibergite (Figure 6(d)).
Mercury minerals are altered, cerargyrite changes and andorite
Mathias had set out a few "new" finds, and was especially proud of a specimen of andorite
with associated zinkenite and stannite from the San Jose mine, Oruro, Bolivia.
In a similar vein (so to speak), I reported last year from Tucson on a new strike of superb specimens of andorite
at the world's best locality for that species, i.e.
), the silver ore minerals may have been franckeite and stannite (both of which commonly bear a few tenths of a percent silver), and sphalerite with micro-inclusions of tetrahedrite.
Last fall saw a major strike of about 150 specimens of andorite
, including what are probably the world's best-ever representatives of the species; at Tucson, Brian Kosnar of Mineral Classics (firstname.lastname@example.org) and Rob Lavinsky of Arkenstone (email@example.com) had the topmost pieces at the Westward Look and at the Main Show, while Alfredo Petrov (firstname.lastname@example.org) proudly showed close runners-up at the Smuggler's Inn.
The San Jose mine officially closed in late 1991, but recent searches for more of its world-class andorite
specimens have produced, instead, a few very fine examples of the rare lead-tin-iron sulfosalt franckeite, these found early in 2003 on the 380 level.
The exhibit also held rare franckeite, andorite
, helvite and canfieldite specimens, all from South America.
Associated minerals are: (dominant) miargyrite; (less frequent) pyrargyrite, stannite and kesterite; (trace) andorite
, diaphorite, robinsonite, galena, chalcopyrite, sphalerite and pyrite.
Associated minerals are: scainiite, zinkenite, boulangerite, robinsonite, tintinaite, sorbyite and other incompletely characterized minerals, Other associated minerals are: sphalerite, cinnabar, galena, andorite
, bournonite, tetrahedrite, chalcostibite, gersdorffite, barite, cerussite and stibiconite.