Knife or scissor dressed sheet mica with irregular shape and a minimum thickness of 0.18 mm (0.007 inch or 7 mils) are called Mica Blocks. Block Mica are classified into thirteen size groups (ranging from OOEE Special down to No. 7) and obtained in size as large as 30 – 35 cm sq. (12 – 14 inches sq.) beyond which is practically rare and far too expensive. It is available in sheets with both random (natural) and calibrated thickness as per demand. After undergoing size and quality grading, Mica Blocks are exported.