Cacholong, a beautiful mineral, regarded as a variety of semi-opal; see OPAL. It is sometimes called Pearl Opal, or Mother-of-pearl Opal. It is generally of a milk-white colour, rarely with a yellowish or reddish tinge.
Cacholong
Chambers's Encyclopaedia, Volume 2: Beaugency to Cataract, p. 611
Source scan(s): p. 0624