cacholong

Century Dictionary and Cyclopedia

1. n. A variety of opal, often called pearl-opal, usually milk-white, sometimes grayish- or yellowish-white, in color, and opaque or slightly translucent at the edges. It often envelops common chalcedony, the two minerals being united by insensible shades.

GNU Webster's 1913

1. n. An opaque or milk-white chalcedony, a variety of quartz; also, a similar variety of opal.