The Warlocks have a earth random. I got the Pebble Skin Suit, then Bloodstone and lucked into a E2 Spectre. Later on I had Belphegor and Pedoseidon.
But there just weren't many earth sites in my lands so I never did much else than some minor forging. Girdles, Crystal Shields etc.
Gem diversity of course improved with conquest.
In the end I had enough air as well for battles, items and domes.