Bruneau Jasper Rough Rock
This natural rough geode or endcut is sliced on one face. It is Bruneau Jasper and it is 3.75 inches by 3.5 inches and 2.75 inches thick.
It weighs 1.64 lbs. and is shown wet in the first picture.
Very well known, Bruneau Jasper is a beautiful stone that comes from the region near the Bruneau River in western Idaho, about 30 miles south of the tiny town of Bruneau. It is sometimes referred to as a porcelain jasper because the cabochons have such a nice porcelain-like finish.
The Bruneau Jasper flow is the most silica-rich rhyolite flow in the area and is predominantly red and brown jasper. The deposit covers several 100 meters and is covered with unpatented claims.
The Greek origin of the word jasper, iaspis, means "spotted stone." This form of chalcedony, or microcrystalline quartz, is usually red, brown or green. Its patterns are much less regular and defined than those of the other chalcedony variety, agate. Another difference between the two is that jaspers are generally opaque, while agates tend to be translucent (or at least contain translucent bands). Jasper has a hardness of about 7 on the Moh's scale.