Steven M. Simmons

Hello,
I bought some antique marbles from a local antique store. They appear to be very old. Five of them are made of real white marble with a baseball seam like groove in them. Two of them are a black stone one shaped like a football. The last is multicolored blue, brown and tan maybe made of clay. All but one of them measure 30mm in diameter and the smallest one is 25mm. Please tell me more about them and what are they worth?
Steven M. Simmons
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