- Siderite 'Box epimorph' after Fluorite
- West Boltsburn Mine, Weardale, Co. Durham, England
- Small Cabinet, 8.4 x 6.6 x 6.0 cm
- Ex. Tim Sherburn
- $9,500.00 Payment Plan Available
This is an amazing specimen in several regards, as these so-called box-epimorphs are so rare and treasured back into the collections of the 1800s, and particularly nowadays. This is a very rare and famous replacement, unique to old England. It is complete by the way, with the fluorite replaced by siderite that overlaid, casts, and then survived and grows in a bit further into the void left as the fluorite simultaneously dissolved during the formation of this specimen. These are thought to have formed at the time the ancient deposit formed, at the end of the primary historic fluorite deposition period itself, and not by later chemical action. This is one of the sharpest we have seen (and we handled the famous ASselborn Box piece, now in a museum collection), for the sharpness, composition, and vertical structure that makes it so displayable. It is complete, free of damage. It is complete all around, and the bottom is a massive hematite matrix, sawed flat so it will sit upright. The crystals reach to just over 5 cm or two inch across, and are sprinkled with little gem calcites. It is 360 complete. One final fact on this excellent specimen released from the Tim Sherburn collection recently, is that it was given to him by his good friend, dealer Cal Graeber, in 2016. Cal, a partner in the Rogerley Mine, had the opportunity to "access" an old entry into the Weardale and go with other collectors down to an area not accessed since the 1800s. These people risked their lives, in my humble opinion - this is not a safe entry or descent after all those years. They were able to find underground and collect fluorite, and some few other specimens such as this, in deposits worked in the times of Sowerby and the great writes of English mineralogy. Among the specimens recovered, was this one (Tim's label notes that Cal self-collected it). To me, one of the most surprising and irreplaceable things in Tim's fabulous, seldom seen collection of English treasures he fastidiously assembled over the last 30-40 years.