Here's a great example of a ?1940's celluloid brooch. It is square with a raised piece in the centre. The pin on the back is a bit crude - as they were at this period. (See picture of back on my web site - www.gillianhorsup.com). Price £30 reference 2589. I always have a selection of 1930/1950's brooches in my shop at Grays Antiques.