Orbicular jasper
Orbicular jasper is a variety of jasper which contains variably-colored orbs or spherical inclusions or zones. In highly silicified rhyolite or tuff, quartz and feldspar crystallize in radial aggregates of needle-like crystals which provide the basis or seed for the orbicular structure seen in this kind of jasper.[1] The material is quite attractive when polished and is used as an ornamental stone or gemstone.
![](../I/m/Jaspe_Orbiculaire_de_Madagascar_1.jpg)
Various local or commercial names have been used for the material, such as kinradite, oregonite, owyhee jasper, ocean jasper and poppy-patterned jasper, depending on the source. Poppy-patterned jasper or poppy jasper is the varietal name for material from several locations, but the most well known is from Morgan Hill, Santa Clara County, California.[2] The trade name ocean jasper is used for a variety found along the intertidal shores of northeast Madagascar. In Nebraska orbicular jasper is found in altered rhyolite beds noted for a variety of jaspers and related agates.
Gallery
- Unpolished poppy jasper, Morgan Hill
- Madagascar orbicular jasper (detail)
References
- "Nebraska". America's Volcanic Past. United States Geological Survey. Retrieved 28 February 2014.
- Hohmann, James (12 November 2006). "City pride built on poppy jasper". San Jose Mercury News. Retrieved 28 February 2014.