Jasper

Hardness: 6.5-7 on Mohs scale. Color: Highly variable, often red, brown, yellow, green, or blue, frequently mottled, striped, or spotted. Luster: Dull to vitreous. Crystal structure: Trigonal (microcrystalline). Cleavage: None. Specific Gravity: 2.58-2.91.

Jasper is a cryptocrystalline variety of quartz and is typically formed as precipitates in sedimentary environments, often found in association with volcanism. It can form through various processes including the lithification of silica-rich sediments or by the replacement of other minerals. Its distinct patterns and colors are due to mineral impurities, primarily iron oxides, incorporated during its formation. Geological age varies widely depending on the specific deposit, ranging from Precambrian to Cenozoic.

Jasper is widely used as an ornamental stone and in jewelry for beads, cabochons, and carvings due to its attractive patterns and range of colors. It is also used for decorative objects, inlay work, and occasionally as a facing stone.

The word 'jasper' means 'spotted stone' and is derived from old French (jaspre) and Latin (iaspidem). It has been used for millennia, with historical artifacts found from ancient Egypt, Greece, and Rome. Different types of jasper are named after their appearance or locality, such as Picture Jasper, Ocean Jasper, and Brecciated Jasper. It is often associated with healing and protective properties in various cultural beliefs.

In the field, jasper is identified by its opaque nature, often vibrant and varied colors, and characteristic patterns (spots, swirls, bands). It has a smooth, waxy feel when polished. It is commonly found worldwide in areas with silica-rich water systems, volcanic activity, or altered sedimentary rocks. Significant deposits are found in Australia, Brazil, Egypt, India, Indonesia (especially Ocean Jasper from Madagascar, but commonly referred to in Indonesia for oceanic varieties), Kazakhstan, Russia, Uruguay, and the United States (Oregon, Idaho, California, Washington).