The mica cleaving process involves insertion of a sharp edge or point into an edge or corner of the mica sheet and gently separating the natural layers of the mica. A thin double edged razor blade is extremely good for this purpose.
The freshly exposed cleaved surface should be used immediately to utilise the clean and even surface. The starting thickness of the mica sheets varies between 0.10 and 0.25mm. The minimum thickness is dependant on the skill of the person doing the cleaving.
Ruby muscovite is a hard material with excellent cleaving properties. It has a minimal tendency to cracking and splits more easily into thin films along natural cleavage planes.