Mica on non-woven backing. Mica or “vermiculite” is a mineral formed out of a chemical reaction between quartz and granite. Exposed to extreme heat, the mineral expands into pieces 2000 or even 3000 % of their original size, in a spectrum of brilliant colours. The characteristics of this mineral have been known in Japan for 6 centuries. Mica is also known as “miracle stone”, or “breathing stone”. After the mica has been heat-expanded, it is crushed into small pieces and glued on a non-woven backing. Finally, the surface is colored.