Diamond Slabs are crafting materials that can be made in a Processor. Like with everything else crafted in the Processor no recipes have to be unlocked for this. 2 Diamond Slabs can be processed from 1 Diamond(Bar) that is made from Diamond Ore in a Forge. Diamond Slabs can then further be processed into 4 Diamond Rods each if needed. Diamond Slabs are used for different crafting recipes, like for Lumite Mining Cells, Diamond furniture and a number of Diamond building blocks too (as of R26 in December 2015)..