we've seen alot of corrupted Gem uncorrupted. But there is one uncorrupted Gem that we havent seen the corrupted form of. Snowflake Obsidian.
There are also several corrupted Gems that we haven't seen uncorrupted. One example is the Flower Monster.
DON'T GO AWAY! I'm not saying they're the same character. But they could be related.
Flower Monsters Gem type has never been confirmed, but to me t looks like a Rainbow Obsidian. Also, FM has the ability to dig and Snowflake used to dig ice trenches. Perhaps FM used to dig a different kind of trench. Not only that, but Snowflake has an eye missing. Assuming this is a corruption scare, this could imply her corrupted form was eyeless.