A yellow oil-like substance, it forms bubbles, even more without gravity.

This substance arguably formed from a similar process to snow, albeit at a far higher temperature.

The basement has never flooded, but a white chalky substance has formed on one section of the wall.

This lava-like substance forms a layer that runs underneath all of Hell.

Any substance, which can be cooled to a sufficient degree below its melting temperature without crystallizing, will form a glass.

These substances can form hydrogen cyanide through subsequent reactions in water.

Other substances form "permanent" magnets and have their own intrinsic magnetic field.

The light-bulb looked greyish, as though a substance was forming on its surface or within.

The heart's substance then engulfs the fiery skeleton and forms a body.

Having said that, I should like to point out that procedure and substance form a whole.