Ferrokesterite (exceptionally fine rare crystals)

Item Description

Here we have a remarkable and superb quality display specimen of what are unquestionably the finest crystals of Ferrokesterite ever found. These specimens were mined in 2004, and were part of the tremendous discovery of the world's finest crystals of Andorite. At first, these specimens were labeled as Stannite, but through analysis by Dr. Bob Downs at the University of Arizona, they were confirmed as the finest known examples of the incredibly rare dimorph Ferrokesterite in existence. Before the Bolivian pieces were found, the best known examples were tiny 1-2 mm "smears" on matrix from the Cligga Mine in Cornwall, England, which is the type locality for the species. The Bolivian specimens are worlds better than anything from Cornwall. You'll notice on this specimen that the crystals are large for the species, and have formed eye-catching crystals with a dark gun metal grey hue measuring up to 9 mm across, sitting on massive Ferrokesterite matrix with minor Quartz. It's rare to find multiple crystals on the same specimen such as this. This is a really super example of an incredibly rare mineral, and considering that nothing has come out of the ground for many years, we probably will never see them again. I was told that the old part of the mine that produced these pieces is completely finished. If you'd like to read the FULL STORY on this history these specimens, please read the article by Brian Kosnar on his website at www.minclassics.com/ferrokesterite.html . For reference, the San Jose Mine has been a source of minerals and metal since the time of the Spanish. The native people in Bolivia were certainly mining silver in this area for many years before any Europeans even arrived in South America. This specimen was priced at $1,800 in our inventory.