Legend has it that back in the 1950s or possibly earlier, Rudy Stefoin and a couple of prospecting friends discovered this gorgeous silicified mudstone somewhere in Wyoming. They never revealed the location to anyone. Some have tried to work it out, but so far it remains a lost bit of prospecting history. Pieces occasionally show up at shows or on eBay, but not very often. A rock seller from Rock Springs, Wyoming, bought what he could from relatives of the late Rudy Stefoin and then sold it on eBay in 2007. I was fortunate to snag some. I have cut quite a lot of it and never tire of discovering what each new piece will reveal. Most of it is a beautiful tan color mixed with clear and black chalcedony and, not as often, the lovely blue color seen in some of the photos below. See the bottom of this page for some thoughts on my experience with slabbing and cabbing this beautiful jasper.

Having slabbed and cabbed many pieces of Stefoinite, I can say that there is a wide range with respect to both pattern and quality of the jasper. Appreciation of the pattern is, of course, subjective. With respect to quality, there is quite a lot of material that has some surface texture (along the lines of the pattern for the most part), healed and not-so-healed fractures and pitting which cannot be avoided always. Some of this texture is actually quite interesting in its own way. Pitting can sometimes be a bit more of a distraction. Within one rock or slab some material can vary in its ability to take a polish. Sometimes the tan areas finish with an attractive semi-matt finish while black, clear and bluish areas take a high polish. This contrast can be just gorgeous. In what I would call A+++ grade, the whole piece takes a beautiful mirror polish, while at the other end of the spectrum some material is either heavily pitted or will not take a polish at all. Stefoinite is a captivating, sublime material with a character all its own.