'Coque de perle' - French for 'eggshell pearl' - given its resemblance to a lustrous, domed eggshell, was a popular faux pearl material used during the Georgian period and carved from the nautilus shell of the East Indies. Often set with pyrite/marcasite or cut steel, pieces were typically crafted in silver to accentuate the steely grandeur of the shell material, though occasionally pieces were set in gold as well.