any of various minerals consisting of hydrous silicates of aluminum or potassium etc. that crystallize in forms that allow perfect cleavage into very thin leaves; used as dielectrics because of their resistance to electricity
"The engineer selected mica for the capacitor assembly specifically because its ability to split into ultra-thin sheets makes it an ideal electrical insulator."
Any of a group of hydrous aluminosilicate minerals characterized by highly perfect cleavage, so that they readily separate into very thin leaves, more or less elastic.
"The geologist carefully separated the mica from the rock sample because its perfect cleavage allowed it to peel apart into flexible, transparent sheets."