I have an antique vanity set labeled 'French Ivory', which is actually celluloid. I suspect that AARC is correct, and you have a 'faux' ivory celluloid piece as well. If you can't find anything while searching 'Colonial Ivory' online, you might try 'French Ivory', 'Ivoride', or 'Ivorine', as they are all names for imitation ivory.