The frosted looking ones have probably been through a rock tumbler. If you want to see what's inside the sulphides or any of the handmades you have, try submerging them in a glass of water and taking a look @ them while submerged.
P.S. Please don't try to polish any marbles in a rock tumbler . They'll have a good chance of hitting one another causing further fractures or completely demolishing them, and you'll be stuck w/ that frosty non see through surface that'll require another professional polishing to remove anyway. Hre is a link to the only person left I know that "might" polish your marbles, his name is Mathew, he has several vids you can watch before ya try and contact him. "Good Luck James""
LINK :: https://www.youtube.com/c/MarbleGems
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