Colored Intaglios

Have you ever seen framed, colored intaglios? I recently saw them for the first time in the dining room of The Jefferson. Makes me wonder - are these colored plaster, Coral or Carnelian?

These two images are from a French blog here - the first image is a collection of both cameo and itaglios. These were noted as coming from the collection of the late Yves Saint Laurent.
Have you seen intaglios that aren't the typical white?