Jasper is an impure opaque quartz, usually containing more iron than
agate, and lacking the quality of translucency. Jasper occurs in red,
brown, ochre-yellow, dark green, brownish-green, grayish-black, and
grayish-blue; sometimes containing bands or spots or quartz formations,
and often found with regular zones or bands of various colors.
Egyptian jasper or Egyptian pebbles are names given to varieties that
are usually brown with inner bands of lighter hue, approaching cream in
color, and sometimes having dark bands with spots or markings.
Egyptian jasper is found near Grand Cairo, and other varieties are
found in the Urals, Saxony, Devonshire, Nova Scotia, Canada, and the
United States.
The specific gravity of jasper varies from 2.31 to 2.67; it scratches
glass, but yields to rock-crystal.