Slate microscope thin section slide exhibiting a slight slaty fabric formed by the growth of mica. The fine grained nature of this common metamorphic rock is obvious in thin section view however slightly larger, bright grains which represent detrital quartz and mica from the original sediment are also present in abundance. Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from a shale ( or similar ) protoliths, they are composed of clay or volcanic ash through low grade regional metamorphism. It is the finest grained foliated metamorphic rock which one can encounter, foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of compression. In hand specimens this Cambrian slate from North Wales can be found in many shades of grey, from pale to dark, and may also be purple, green or cyan. The glass is 46 x 27 mm in size, supplied in a protective card sleeve with a label, ideal for microscopy, petrography & educational use.