Colorful, 2.85" Polished Jasper Bowl
This is a 2.85" wide polished "fancy jasper" bowl that was collected in India.
Jasper is a term that can be applied to an opaque variety of chalcedony (light does not pass through it) The opaqueness is due to a much larger amount of impurities mixed with silica/quartz. Like agate it may form in a huge variety of colors, and is often multi-colored. In most cases, jasper will occur when silica-rich fluids permeate throughout a soft sediment or volcanic debris deposit. The fluids then crystallize around the particles/impurities, resulting in a cementation process. Most often, the impurities present determine the coloration of the deposit following solidification, however other factors can play a role in the color of what is now considered a jasper.
Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.