Knife dressed Sheet Mica of a minimum thickness of 0.18 mm (0.007 Inch), is called Block Mica or Mica Blocks. Block Mica is obtained in size as large as 30 to 35 cm. sq. (12 to 14 Inches sq) beyond which is practically rare and far too expensive. It is available in sheets with an average thickness between 0.18 - 0.75mm (0.007 - 0.030 Inch). Block Mica is supplied both in natural (random) and calibrated thickness as per customers demand.
These are the mica blocks of various different origins in India. They all have mostly similar properties besides the color & temperature resistance. Their dielectric properties differ too. ruby mica is the most sustainable in all forms across all types.