I believe these are a bisque type of glass... i didnt mean to confuse anyone when i stated they were not glass, just new to this. I am away on business but when i return next week i will try to do additional pics and will measure the marble. I would say its on the larger size and all three are pretty close in size. I tried to show it next to a penny to give a general idea. Im not sure on the pontils, will have to re-examine. Thanks all for your input.