Dust

Dust is the main form of energy in the world of RWBY.

History/Mythology
According to the opening narration in the first episode, mankind was in a losing struggle with creatures of darkness known as Grim. However, man's passion, resourcefulness, and ingenuity allowed them to discover and harness the power they titled Dust (implied to have been named after the force they rose from) in order to battle the monsters. Since the ancient times when mankind drove these beasts away and built civilizations, it seems to have become a part of everyday life in the RWBY world.

Production and Distribution
The Schnee Dust Company is one of the largest producers of Dust in the RWBY world. Dust mined from the Schnee Quarry is transported by railway lines.

Dust is sold in shops, such as From Dust Till Dawn. It comes in different forms of matter, like crystal and powder. Crystals are apparently safe enough to leave out on display like common jewelry, but tubes lining the walls seem to contain a version that was in a powdered form. The only difference between the crystal and powder form of dust is that the crystal form is weaker. The way that Dust works is a mix between fuel, batteries, and personal energy. Roman Torchwick and his henchmen were able to take the powderized Dust  with cylindrical devices that attached to the mouths of the tubes and allowed them to contain and transport it. Other bags on shelves were seen that were the same bright hues as the tubes and their Dust, but whether or not they contain Dust themselves is unknown.

Types of Dust
Dust most likely has different effects with each form, as seen when Ruby sneezed, easily igniting powdered red Dust. It also seems that there are different attributes with each color. Weiss in Episode 2 identified 4 types of Dust: Fire, Water, Lightning, and Energy (possibly referring to Dust in general). We can assume the color coordination of Dust shown below by the table. We have yet though to see the everyday use of Dust, but it can easily speculated as electricity or a similar type of fuel.

* "Smoke" is an unofficial fan name for an extremely rare, powerful, and illegal Dust type that does not adhere to the properties of normal dust. It first came up as possibly the animating force behind the Giant Armor battling Weiss in the "White" Trailer, and since has been speculated to have some connection to the Grim. However, the existence of "Smoke" or any similar Dust type has not been confirmed.