Not exactly sure of the material. Not the traditional die that can crystallize. They are white/off white. And show almost no wear. The pips are ringed and inset slightly. These were given to a friend many years ago (maybe as much as 40 years). She tells me that he worked as a pit employee in LV. Not sure where. It’s not really that important, more curious than anything. I have seen white dice before, and don’t know what the material was then either. These are very similar in look to some Hard Rick white dice I had years ago. Thanks for your response!