Thank you (and @pie_flavor) for the replies.
Yes, I believe they are using metadata, the same way vanilla minecraft diorite is just minecraft:stone:1 (or 2 or whatever number). You are correct that they seem to be moving away from this way in favour of “block states”… which I assume diorite in my example above would become minecraft:diorite.
1.13 seems far away though, and a big update that many servers, mods, plugins might take a while to catch up to. Is there no way, even by editing the config files to use the ic2:resource:1? How do others here currently give experience for players mining diorite or granite?
Thanks again, great and essential and fun plugin!