âºâº Definition: Ton. The short ton is a unit of mass equal to 2000 lb (exactly 907.18474 kg). In the United States it is often called simply ton without distinguishing it from the metric ton (or tonne) and the long ton rather, the other two are specifically noted.
Pumice is a light-colored, extremely porous igneous rock that forms during explosive volcanic eruptions. It is used as aggregate in lightweight concrete, as landscaping aggregate, and as an abrasive in a variety of industrial and consumer products.he abundant vesicles in pumice and the thin walls between them give the rock a very low specific gravity. It typically has a specific gravity of less than one, giving the rock an ability to float on water.
Background: Pumice is a type of extrusive volcanic rock, produced when lava with a very high content of water and gases (together these are called volatiles) is extruded (or thrown out of) a volcano. As the gas bubbles escape from the lava, it becomes frothy.umice and obsidian are often found together. In commerce, pumice is the term applied to larger pumice stones, while pumicite consists of fine grains or ash. Pozzolan is a fine-grained pumicious material (both natural and man-made), which combines with lime to make a smooth, plaster-like cement.