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.
Igneous Rocks and Formations. Following you will find some examples of igneous rocks. 1  Pumice is a light colored and lightweight igneous rock ejected from a volcano at very high heat and pressure. 2  Gases escape as the rock hardens, leaving bubbles and holes throughout the rock, and resulting in its light weight.