Pennsylvania jasper, Berks County, Pennsylvania.
Jasper comes from the Hardyston Formation, generally found at the top of the formation. Jasper is most prevalent in the eastern portions of the formation, in discontiguous pods. The parent material is quartzite, with jasper formed by hydrothermal replacement. The sample was collected south of Bowers, Berks County, Pennsylvania.
The jasper is commonly lustrous and waxy, red, yellow, and brown colors, often with veins of clear drusy quartz or coatings so botryoidal chalcedony (sometimes bright orange or purple). It can be homogenous in color and texture, brecciated, or display dendritic structures. It heat-treats well. High quality jasper grades into dull grainy material that was minimally exploited.
Prepared By Ebright 1999
Updated October 22, 2016