Asphalt is a black building block with a rough surface, different from the shiny block indicated on its icon.
It can be crafted in your Crafting Menu (default key "q") after the according crafting recipe has been unlocked by
- obtaining a Glob of Goo as a random loot or harvest from most surface Creatures, or created in a Processor from blocks of Mold (mined on the Stalactite layer underground with at least a Stone Mining Cell equipped or better)
- obtaining (a block of) Fossils, usually mined from the Fossil layer (accessible through shallow Caves) or from recesses close to rivers, which does not require any Power Cell to be equipped
To craft 8 blocks of Asphalt, you'll need (as of R44 in June 2017)
- 2 pieces of Coal, extracted from Coal Nodes in Mountains or on the Fossil layer underground by using any kind of Extractor, or found in Wood Treasure Chests on the surface, or obtained from Keepas of any kind
- 1 (block of) Fossils mined from the Fossil layer or from recesses close to rivers, which does not require any Power Cell to be equipped
- 1 Glob of Goo made from Mold in a Processor or looted/harvested from many creatures
Running across Asphalt blocks does not boost the speed of running.