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.
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.
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.
A fine and attractive example of this rare Lead, Silver, Antimony "black ugly" mineral! Until the 2004 find, Andorites were one of the rarer Sulfosalts and crystals were always quite tiny. This piece is from that discovery and a very good value for the size, condition and form. The metallic luster and steel to brassy hues are as good as these ever get. Ex Kosnar, there are now very few of this caliber to be found, lesser pieces are typically far more expensive!
A very fine, esthetic and pristine example with very well formed twinned prismatic crystal. These are well positioned and free standing with excellent luster. Individual prism reach 2CM and the matrix is well crystallized arsenopyrite for a nice contrast. Nearly all Viloco Cassiterite comes out damaged, this large piece is a rarity as there is only very minor chipping at a a few edges that are not obvious, it is virtually pristine. Displays well from many angles.