Volcanic tuff (originated from Italian tufo* a.volcaniktuff - explosion tuff) – sedimentary rock from volcanic ash, volcanic bomb and other fragments, ejected during volcanic explosion and then concentrated. It is very dense and solid. The unique feature of volcanic tuffs is angularity of fragments and their ungradedness; they are subdivided according to the structure, nature and proportions of the fractions. Tuffs have diverse coloring: yellow, orange, violet, pink, red, brown, grey and black. Tuff differs from other types of trim stone by wide range of bright and saturated tints.