Jasper Gemstone Information
Jasper is one of the many gemstone varieties of quartz available today. It is an opaque and impure variety of silicon dioxide (SiO2).The name 'jasper' is derived from the Greek word for 'spotted stone', referring to its typical multicolored, striped, spotted or flamed appearance. Jasper can form in virtually any color. Jasper is usually considered a chalcedony, but some scientists classify jasper as a separate type because of its distinctive grainy structure.
Jasper is a dense substance, up to twenty percent of which can be made of foreign materials. Due to these trace impurities, jasper is rarely uniform. In some cases, jasper may even grow together with agate or opal. The patterns of jasper are formed during the process of mineral consolidation, determined by the exact flow and deposition of silica-rich sediments or volcanic ash.
Jasper is often modified by other intruding impurities. As original deposits of silica materials naturally form with fissures and cracks after deposition, they are later filled by other minerals, such as iron oxide, manganese dioxide, metal oxide and sometimes organic matter. The final settling of these materials determines the specific appearance of the final substance.
The most common jasper patterns include interesting marbling and veining, orbital rings, streaks, spots, flaming and banding. Like agate stone, there are numerous trade names and classifications used for jasper today. The names can be very confusing, but fortunately, most are used only by the most avid collectors.
Jasper Gemological Properties:Chemical Formula: SiO2 - Silicon dioxide
Crystal Structure: Trigonal - microcrystalline aggregate
Color: All colors, mostly striped or spotted
Hardness: 6.5 [fraction] to 7 on the Mohs scale
Refractive Index: 1.54 (approximate)
Density: 2.58 to 2.91
Luster: Dull, vitreous