Coque de perle, from the French for 'pearl shell' was a Georgian faux pearl carved from the East Indian nautilus shell. The central whorl of the convex part of the shell was cut away to form these delicate "eggshell pearls." Filled with cement to stabilize it, coque de perle was very popular because of its high level of iridescence.
Coque de Perle Necklace in silver set with diamonds. English circa 1740-1760. © Victoria & Albert Museum.
Coque de perle is found set with cut steel
jewelry or with pyrite
and, very occasionally, in gold