Dirt

Dirt block, made of environnement friendly elements such as :

-dirt

-gravel

-organic elements (mashed wasps)

the Dirt block isn't available via creative inventory, it's only available via NEI or commands.

[WARNING]

in any case, dirt should NOT be in contact with anything as it may cause a False Vacuum!

"DIRT IS THE SALVATION"

Right-clicking it with a brittle spade will make it drop the 3 "elements" needed to craft Metastable-U238