I don't mind. I like revisiting mysterious marbles.
1.83 inches.
I wasn't sure what we said about it before, but when I did the size conversion, I became fairly sure what we would have said. At that size I can only think of one option.
I could hope it was some super rare dug Akro, but that is huge, so it leaves me with only one practical choice.
( @Alan, it's not some super rare dug Akro, is it? )