Rock of the Month
The monochromatic red color of this jasper (opaque-to-sub translucent chalcedony or microcrystalline quartz) is from disseminated hematite. Later blebs of colorless milky white chalcedony can be seen to have infiltrated brittle cracks and pods of textural disruption in the jasper. Northern California has several areas of differing red jasper, especially on the eastern mountain ranges and very nice specimens at Black Butte reservoir.
Updated Feb. 4, 2015