Imitation Tortoise Shell Fan

This spectacular fan is from our family's treasure trove. I believe it is from the 1920's or 30's. It belonged to either our Grandmother or her mother. It is in good condition especially considering it's age. The ribbon holding it together is intact and none of the blades are broken. It looks like it had a loop or something at the hinge that has broken off, see picture. We have determined that it is not real tortoise shell by looking at it through a microscope. Real Tortoise shell has the colour made of tiny brown spots, unlike this. We also confirmed our conclusion with uv light and it did not fluoresce. Real shell fluoresces blue and white, this did not react to the uv light at all.