Cryolite occurs in colourless or snow-white cleavable masses, often tinted brown or red with iron oxide, and occasionally passing into a black variety.

Mica: this term includes several minerals, which all agree in being highly cleavable into thin elastic flakes or lamin�, which have a glistening metallic lustre.

Large, cleavable masses yielding fine smoky-black and green sheets, sufficiently elastic for industrial purposes, are, however, found in Renfrew county, Ontario.