I have one just like it in my collection. https://www.ebay.co.uk/itm/Large-Antique-Glass-Marble-33mm-Diameter-with-Mica-Inclusions-Polished-Pontil/133342677195?hash=item1f0bd7c8cb:g:tNIAAOSwlq9eUrzZ&LH_ItemCondition=3000
I will do. I've got so many marbles literally lots of old tins and jars full of them I'll have a look and snap a photo later as it may take me a while to find it.
Here's another auction... for a bunch of common not very old coins. That George III coin is a re-strike. I wonder how much that lot will sell for.