Occurrence:
Worldwide. A member of the chalcedony family
(micro-crystalline quartz).
Appearance:
Onyx is the name given to chalcedony which
is uniform in color, generally black or white. Onyx should not be confused
with onyx marble, a banded stone which is a form of limestone (calcite
or aragonite).
Something Extra:
Onyx was very popular with the ancient Greeks
and Romans. The name comes from the Greek
word onux, which means fingernail. The story
is that one day frisky Cupid cut the divine fingernails
of Venus with an arrowhead while she was sleeping.
He left the clippings scattered on the sand and
the fates turned them into stone so that no
part of the heavenly body would ever perish. True, black
isn't normally the color one associates with
fingernails. (Did Venus wear Vamp?) But in Greek times, almost all colors
of chalcedony from fingernail white to dark brown and black were called
onyx. Later, the Romans narrowed the term to refer to black and dark brown
colors only.