Water

Water is one of the Materials in Mechanic Miner.

Looks
Water, a blue cube.

Where
Water is one of the first materials you'll encounter, along with Copper. It can be mined from any freshwater source, but not from the sea (since you need freshwater, not salty sea water).

Use
Water is a fuel type material, and so it's not used to build anything. Use water to power boilers on vehicles, and make sure you carry some water with you in case your vehicle runs out of fuel.