Slightly better wording is 'When one of your creatures dies', but it's not a huge deal.
As a mechanic, this doesn't really fit earth, but I can't see it fitting in any other element either. It's a completely different mechanic than basically anything else in the game, so with the right theme, it can fit anywhere. The element fits the name and the name fits the mechanic, so the theme is still solid.
As far as balance goes, there's nothing in the game you can really compare this to. The card is generally most useful with high-cost creatures, especially fragile ones, but isn't too great anywhere else. I think a cost to 6|5 or lower should be good.
Nice idea, hope you're able to get it into the system easily :3