Solid lubricants may be graphite powders that are specially ground by a specific process to obtain:
- grain size adapted to the use,
- or molybdenum disulfide,
- or boron nitride.

In the case of graphite, the compound exhibits a laminar and hexagonal crystalline structure whose lubricating effect is exclusively the result of the crystals sliding against one another (in much the same way as a "deck of cards").