King James Bible Dictionary

(Heb. yashpheh, "glittering"), a gem of various colours, one of the twelve inserted in the high priest's breast-plate (Exodus 28:20). It is named in the building of the New Jerusalem (Revelation 21:18, 19). It was "most precious," "clear as crystal" (21:11). It was emblematic of the glory of God (4:3).

A precious stone set in the high priest's breastplate.
Exodus 28:20; Exodus 39:13; Ezekiel 28:13; Revelation 4:3; Revelation 21:11; Revelation 21:18-19

a precious stone frequently noticed in Scripture. It was the last of the twelve inserted in the high priest's breastplate, (Exodus 28:20; 39:13) and the first of the twelve used in the foundations of the new Jerusalem. (Revelation 21:19) The characteristics of the stone as far as they are specified in Scripture, (Revelation 21:11) are that it "was most precious," and "like crystal;" we may also infer from (Revelation 4:3) that it was a stone of brilliant and transparent light. The stone which we name "jasper" does not accord with this description. There can be no doubt that the diamond would more adequately answer to the description in the book of Revelation.

J'ASPER, noun [Latin iaspis.] A mineral of the siliceous kind, and of several varieties. It is less hard than flint or even than common quartz, but gives fire with steel. It is entirely opake, or sometimes feebly translucent at the edges, and it presents almost every variety of color. Its varieties are common jasper striped jasper Egyptian jasper etc. It admits of an elegant polish, and is used for vases, seals, snuff-boxes, etc.

Jasper is a subspecies of rhomboidal quartz, of five kinds, Egyptian, striped, porcelain, common, and agate jasper

J'ASPERATED, adjective Mixed with jasper; containing particles of jasper; as a jasperated agate.