Modern jasper is an opaque variety of quartz containing an admixture of iron oxide. Its colors, often arranged in layers, are white, red, yellow, brown, or black. Jasper is harder than glass and is found in metamorphic rocks in mass or as distinct crystals. The best grades are used for gemstones and can be highly polished. Some scholars, however, believe that, since the jasper (Gr., iʹa·spis) at Revelation 21:11 is called “a most precious stone . . . shining crystal-clear,” the ancient stone may have been of greater rarity and value than the comparatively inexpensive modern jasper, and brilliantly translucent rather than opaque. Some scholars have suggested that the Greek term in reality refers to the diamond.

A stone of jasper (Heb., ya·halomʹ) representing one of Israel’s 12 tribes was placed in the last position in the second row of stones on Aaron’s “breastpiece of judgment.” (Ex 28:2, 15, 18, 21; 39:11) The jeweled “covering” worn by the king of Tyre was adorned with jasper. (Eze 28:12, 13) In the vision of Jehovah’s heavenly throne of splendor, John observed that “the one seated is, in appearance, like a jasper stone and a precious red-colored stone.” (Re 4:1-3, 10, 11) “The holy city, New Jerusalem,” is described as having a radiance like “a jasper stone shining crystal-clear.” The structure of the holy city’s wall was jasper, as was the first foundation stone.​—Re 21:2, 10, 11, 18, 19.