Silica

Silica, also known as silicon dioxide and could be found in the soils of thousands of planets.

Silica as a Weapon
The Rakata would destroy planetary environments by orbitally bombarding the surface  originally composed of soil. The silica in the soil would be fused into glass, which then broke up over time into sand. In the case of Tatooine this was done and it boiled its oceans away.