Light Gray Tuff, a Fine-Grained Volcanic Rock - 10 Raw Pieces
Tuff Fine-Grained Volcanic Rock, 10 Pieces
by American Educational Products
Tuff is a rock that is made of volcanic ash that has been ejected from a vent during an eruption. After being deposited on the ground, the ash gets compacted into a solid rock by way of consolidation. This refers to a process by which soil decreases in volume due to stress being applied to the soil (ash, in the case of Tuff), resulting in the water content being squeezed out of it.
Sometimes called tufa, is should not be confused with the actual rock known as tufa, which is a type of limestone. Relatively soft, Tuff has been a staple in construction since the time of the Romans, who used it because of its abundance in Italy. It was also used by the Rapa Nui of Easter Island to create the famous moai statues on the island.
Because of its volcanic origins and subsequent consolidation, Tuff is capable of being classified as being both sedimentary and igneous, though it is primarily studied within the context of the igneous rocks.