I get asked often and the answer is both simple and complex. The simple answer: Jasper is a opaque silica based material with conchoidal or "shell-like" fracture like how glass breaks and a hardness of 7, which cannot be scratched with a steel pocket knife, just like quartz, why?
The complex answer: jasper is NOT a scientific term. When labeling proper jaspers, scientists will label the specimen "cryptocrystalline quartz or microcrystalline quartz: variety jasper". What is this silica of which I speak? Silica is the combination of the elements silicon and oxygen. Silica, being the building blocks of quartz, moves around freely in water and more freely in saline water. It acts like a plastic, looking for places to form globs where ever concentrations occur.
What we know about jaspers, since you cannot see visible crystals, is that they were formed in a fairly cool temperature events, as the more heat you introduce, the more sugary the texture becomes as the silica solidifies into quartz.
Not all jasperoids are jaspers though, so what is the difference? Saturation of silica. Jaspilite is a banded iron formation rock that often has distinctive bands of jasper. 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 multicoloured, striped, spotted or flamed appearance. Jasper can form in virtually any colour. 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. There are also quite a few stones called jasper in their common name that consist of different minerals than true jasper.
One of the most famous is Dalmation Jasper, which is a microcrystalline silica stone instead of a cryptocrystalline stone. And Where To Sell It. Imperial Jasper is a pricey stone, so there are quite a few artificial substitutes out there. Testing is usually easy, most will burn readily if you apply a hot nail or needle to the stone. Looking for information on rockhounding in your state or around where you live?
Easily find all of our articles by individual states! Jasper, like agate, can be found in most places that formerly had volcanic activity. Prospecting for jasper can be done very casually, and you may find some striking local varieties.
Search online for areas near you that may have jasper. For instance, you can find club field guides that provide a realistic overview of most areas. Scouting areas with Google Maps can often help. Walking riverbeds is the best way to find jasper nodules in an area. Riverbeds collect stones over time, and dry ones are a treasure trove.
The Mineral jasper. Jasper is an opaque form of Chalcedony , which is a microcrystalline variety of the mineral Quartz. It often contains an abundance of impurities , and therefore some regard it as a rock instead of a mineral. Jasper is usually associated with brown, yellow, or reddish colors, but may be used to describe other opaque colors of Chalcedony such as dark or mottled green and orange. Some forms of Jasper are banded , and these banded Jaspers may appear similar to Agate , but unlike Agate they are opaque.
When Jasper is dull and lacking interesting colors or patterns, it is not Jasper but rather Chert. For additional information, see the gemstone section on Jasper.
There are several variety names for Jasper generally used by collectors and dealers, but there is also an abundance of variety names that are made up by dealers to describe a locality or other habit.
The varieties section below will only list well-known names that are commonly used. Agate Jasper. The proper definition of Basanite is a low-grade Obsidian. Biggs Jasper. Brecciated Jasper. Bruneau Jasper. Cave Creek Jasper. Deschutes Jasper.
Egyptian Jasper. It is found as rounded pebbles on the beaches of Egypt. A similar Jasper is found on the beaches of Washington state and sometimes also labelled as Egyptian Jasper. Green Jasper. Green Jasper differs from Prase and Plasma since it is fully opaque. Leopard Jasper. Morgan Hill Jasper. Sometimes synonymous with " Poppy Jasper ". Moss Jasper.
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