ジャスパー Jasper is derived from the Greek for "spotted stone". Jasper is usually considered a chalcedony, but scientists put it in a group by itself because of its grainy structure. Finely grained, dense jasper contains up to twenty percent foreign materials that determine its color, streak and appearance. Uniform jasper is rare; it is usually multicolored, striped, spotted or flamed.
Chrysoprase, a bright apple green translucent chalcedony, is the most valued. Some treasured jasper stones exhibit a picture that appears to be taken from nature and are called "landscapes". Another specialty is bloodstone or blood jasper, also known as "heliotrope"; a dark green chalcedony or jasper with flecks of red. Most jasper is opaque and takes an excellent polish. Jasper is used for ornamental objects, cabochons and stone mosaics. Care must be taken during cutting. Banded jasper tends to separate along the layers.