Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
From a Latin word tophous then in Italian tufo and finally tuff
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
From French schiste, Greek skhistos i.e. split
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock