The Diamond Roof is a slanted building-block with a non-transparent tiled bright blue topside and a white limestone-wall-like underside.
This slanted block can be placed to create corners of walls or for other purposes too when being rotated by pressing and holding R (as the default key) while moving the mouse.
It can be crafted in your Crafting Menu (default key "q"), but only after the crafting-recipe has been unlocked by
- creating Diamond Slabs by putting Diamond bars into a Processor. Diamond Ore can be extracted from Nodes found on the Lava layer underground or made from Coal Nodes with Fire Bombs
- creating Diamond Rods by putting Diamond bars into a Processor
- crafting or taking Iron Roofs (unlocked after crafting/taking Obsidian Roofs).
Crafting or taking Diamond Roofs is one of the unlocking requirements for the crafting recipe for Lumite Roofs.
To craft 8 (blocks of) Diamond Roofs, you'll need
- 1 Glob of Goo made from Mold in a Processor or looted/harvested from creatures
- 1 Iron Rod made of an Iron Bar in a Processor
- 2 Diamond Rods made of Diamond bars in a Processor
- 4 Diamond Slabs made of Diamond bars in a Processor