jasper A variety of chalcedonic (see CHALCEDONY) Silica (SiO₂) which is reddish-brown, opaque, and cryptocrystalline. It may be banded to give ‘Egyptian jasper’ (‘ribbon jasper’). A contact metamorphosed (see THERMAL METAMORPHISM) shale may also be baked to give ‘porcelain jasper’ which may be similar in appearance but has a different composition.

jas·per / ˈjaspər/ • n. 1. an opaque reddish-brown variety of chalcedony.2. a kind of hard fine porcelain invented by Josiah Wedgwood and used for Wedgwood cameos and other delicate work.

Jasper

A variety of quartz to which many medicinal values were attributed in ancient times. It was believed to prevent fever and dropsy, strengthen the brain, and promote eloquence. It was said to prevent defluxions (discharge of catarrhal mucous), nightmares, and epilepsy and was often used in the East as a countercharm. Bishop Marbodeus mentioned 17 species of this stone but noted that, like the emerald, it was mainly sought for its magic properties. As late as 1609 it was still believed that jasper worn about the neck would strengthen the stomach.

jasper originally, any bright-coloured chalcedony other than carnelian; now, an opaque reddish-brown variety of chalcedony. In the Bible, jasper is the name of a stone in the high-priest's breastplate (Exodus 28:20); it is also one of the stones in the wall of the New Jerusalem (21:18).

jasper XIV. — OF. jaspre, var. of jaspe — L. iaspis, -id- — Gr. iaspis, —id—, of Oriental orig.