(n) :
(in present times) a fine-grained white or lightly-tinted variety of gypsum, used ornamentally; (in ancient times) a variety of calcite, translucent and sometimes banded
(n) :
(in present times) a fine-grained white or lightly-tinted variety of gypsum, used ornamentally; (in ancient times) a variety of calcite, translucent and sometimes banded