Explanatory notes
… die-punch, their edges are clean cut. Natural mica is often used as such in the form of sheets or splittings. However, … high cost, etc., render natural mica unsuitable for many uses, it is frequently replaced by agglomerated (built-up) … bonding mica splittings one above the other or side by side using shellac, natural resins, plastics, asphalt, etc. …