A complex small specimen with two main large Bismuthinite crystals that are covered with tiny crystals of Stannite and Marcasite. The specimen also has areas of Chalcopyrite as well as some tiny needle crystals of Bismuthinite that seems to be a later generation. A choice example of the thicker type of Bismuthinite crystals and a nice association of these two Sulfides. From a recent find that was premiered in Munich in October 2019.
Bournonite - Cogswheel type crystals
Colavi Mine, Machacamarca district, Cornello Saavedra Province
3.1 x 2.6 x 2.4 CM (small miniature/ large thumbnail (toenail))
A fine complete cogswheel cluster of Bournonite crystals that is perfect on all sides, undamaged and with classic gunmetal luster. Bournonite is a delicate mineral and perfect clusters of this sort are quite rare. A tiny bit of adhering matrix gives some nice contrast. This is a very fine and unusually sharp specimen from Bolivia that really looks just like a vintage Herodsfoot specimen. From recent mining this is obviously far less expensive than the English classics!
A lustrous cluster of mostly Pyargyrite crystals that at first glance appear a silvery black color. Strong light shows some brilliant red zones of ruby silver, and with magnification are some classic twinned Polybasite crystals as well. Minimal matrix, the associated Sulphides are only seen with magnification. Some edge chipping is noted, not easy to see by naked eye (this is a brittle mineral ) but the main crystals are in fine condition, some with textbook forms. The Pyrargyrites have some unusual habits on this piece, it is an attractive small miniature with very bright flash., could trim to a very strong thumbnail if desired
Sharp replacement of hexagonal Aragonite crystals by native copper. Excellent form, complete on all sides and with classic hexagonal prisms. Slightly hoppered on flat faces, this is formed of two textbook prisms that intersect on one narrow edge. Usually these pseudos are rather crude, it is very special when such sharp detail is preserved.
Cassiterite variety Needle Tin
Minera Monserrat, Challapampa, Poopo Province
5.6 x 5.5 x 3.4 CM (cabinet)
A very unusual specimen from Boliva that looks like an old Cornish "needle tin". A three dimensional matrix densely covered with delicate accicular crystals of brown Cassiterite. In fine condition as seen, ex. Hitchings collection. Especially impressive under magnification, this is an uncommon habit and a well crystallized example.
Vivianite -Single gemmy crystal
Tomokoni Mine, Machacamarca District
4.5 x 2.3 x 1.3 CM (miniature)
A gem clear single crystal with excellent dark green to bluish color, and glasslike luster. Sharp and elegant, this is at its best with some backlight to bring out the inner colors. On the backside some small matrix is adhering, but mostly this is a single, loose crystal. Typical curving of the termination can be seen at some angles. Choice older specimen from 1980 vintage finds, excellent condition.
A killer Potosi Bournonite with large, perfect crystals showing classic form. Complete all around, a perfect floater with no matrix, just big metallic Bournonites in fine condition. The largest crystal is a sizable 3.8 CM and all the crystals have a gleaming gunmetal luster. This is from the remarkable find in 2007-8 which had the very best Bournonites ever seen from Bolivia and some of the best ever found on the planet. This is very much a top percentile specimen from that discovery, a true top shelf piece.
San Antonio Mine
Loayza Province, La Paz department,
5 x 3.4 x 2.2 CM (miniature)
pre Tucson 2015 update
One of the oldest and best localities for fine Cassiterites in the Americas is the La Paz area of Bolivia. This specimen has well formed and lustrous crystals that under strong lighting show some translucence. The "naked eye" color is shiny black but the "under strong lighting" color is a deep honey orange hue. Some tiny edge chipping exists but most crystals are pristine and the quality for the price is a very good value.