Pumice Pumice, a porous, glassy form of lava formed during volcanic explosions.

Silica gel is a granular, vitreous, porous form of silicon dioxide made synthetically from sodium silicate.

Replies: Susan V., Charcoal, wood is a highly porous form of amorphous carbon made from the destructive distillation of wood.

Silica gel is a granular, porous form of silica made from sodium silicate.

Robert Gore was granted a patent on April 27, 1976, for a porous form of polytetrafluoroethylene with a micro-structure characterized by nodes interconnected by fibrils.

Their alumino-silicate construction is extremely durable and resistant to radiation even in porous form.

Pultost is found in two forms, spreadable and porous.

Platinum sponge is a porous, grayish-black form of platinum.

It shows a porous form of bronze, virtually unknown for that period, and museum officials say the cat is probably a fake.

Travertine Travertine, a soft, compact or porous form of limestone.