Graphic texture
From Wikipedia, the free encyclopedia
The feldspar is white and roughly 10 x 10 centimeters. Quatz are the little cuneiform and gray ones
Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in igneous rocks. It is called 'graphic' because the exsolved or devitrified minerals form wriggly lines and shapes which are reminiscent of writing.
Trachyte is a volcanic rock which typically has graphic texture. Devitrified obsidian and other volcanic glasses typically develop graphic textures; pepperite is a typical rock formed by this process.
Graphic granite is a leucocratic granitic rock consisting of alkali feldspar with exsolved quartz typically forming a distinctive repetitive pattern sometimes resembling the old Sumerian cuneiform writing. (see picture right)
Exsolved magnetite has graphic texture, as do some exsolution textures of pyroxene, pyrite feldspar and rarely other minerals.
