Specification :

Basalt is a dark, fine-grained, igneous rock consisting mostly of plagioclase feldspar and pyroxene, and sometimes olivine. It makes up most of the ocean floor and is the most common type of lava. It has been commonly applied in construction area
There are three main trypes of lava according to the size of holes. Basalt can be processed as polished, honed, flamed, bushhammered, sandblasted, natural split and so on.