Home >> British Encyclopedia >> Inflammation to Language 1 >> Jasper

Jasper

found, striped and occurs

JASPER, in mineralogy, a species of the clay genus, divided by Werner into six sub-species, viz. the Egyptian, the striped, the porcelain, the common, the agate, and the opal jasper.

The Egyptian jasper exhibits two or more colours in concentric zones or bands, more or less regular, with interspersed spots or dendritic figures. It is brittle, and the specific gravity is about 2.6. It occurs in rolled pieces, which are mostly spherical. Before the blow-pipe it is in fusible without addition. It is found in Egypt and the adjoining desarts, and, on account of its beautiful colour and great hardness, it is used for similar ornamental and useful purposes as the agate The colours of the striped jasper are grey, green, yellow, and red ; these are often found together, and arranged in striped and flamed delineations. It occurs in large beds in Saxony, and also in Si beria, where it is of a very beautiful kind. It admits of a high polish, and is used for purposes of ornament chiefly. It derives its name from the striped colour delinea tions with which it is marked. The por

celain jasper generally exhibits but a sin gle colour, and is sometimes marked with cloudy delineations. It melts before the blow-pipe, and is found to consist of It occurs in beds in pseudo-volcanic hills, and it is supposed that it is slaty clay, converted into a kind of porcelain by the action of fire. It is found in great plenty in Bohemia.

The common jasper is found generally in veins that occur in primitive rocks in many parts of Europe. It is susceptible of a high polish, and is in considerable re quest for ornamental purposes. Opal jas per is found in nests, in porphyry, near Tokay, in Hungary, in the neighbourhood of Constantinople, and in some Siberian mountains. It is supposed to bethe con necting link between jasper and opal, and is distinguishable by the liveliness of its colours, its superior lustre, and constant conchoidal fracture.