can i make light concrete with vermiculite?or other material?
Small white balls that look like syrofoam that you put in with potting soil or dirt to absorb water.
It is a potting agent that aerates dense soil. You`ve seen the little white specks in soil from the garden centre, that`s it.
Vermiculite is expanded mica, a layered mineral. It is composed primarily of silicon and so it is very stable chemically. Because it is low density, it makes a good insulator and lightweight filler for such things as spackling compound. Its drawback in using for insulation is that is settles with time and therefore surrenders some of insulating property. If used in walls, it will leave an uninsulated area at the top of the wall.
Stevetower's answer is correct. It is also used in potting soils, but is NOT the white specs. Those white specs are a form of expanded volcanic ash. Vermiculite looks like shiny flakes. Both uses are common. It is also used as a packaging material. It is expensive but is fire-proof so is used for insulating around chimney stacks and for packaging around containers of flammable liquids. CAUTION: It is suspected of being a possible source of lung cancer, like asbestos, if its dust is inhaled.