MICA was founded 188 years ago, but mica was founded somewhere around 4 billion years ago. Mica is a mineral known chiefly for its near perfect cleavage- rest easy, internet censors, we’re only using the scientific term for the tendency of crystalline materials to split along definite lines!
Because mica cleaves so finely, it can be made into incredibly thin sheets which we humans have found to be quite handy: sheet mica is prized in space and other high-tech industries for its unusual ability to act as both electrical insulator and thermal conductor.
In the 19th and early 20th centuries, mica’s near perfect cleavage also made it valuable as a sturdier alternative to glass. When separated into fine sheets, mica is nearly transparent, but it has a much higher tolerance to temperature changes. This made it an ideal material for peepholes and windows in lanterns, stoves and boilers.
In the basement of 2418 Eager Street, we found an envelope of Munsell’s Mica. It appears as though Mr. Munsell got into the mica business in the 1890s, though his brand wasn’t registered until 1908. His product shows up in the list of patents and labels from that year, right after “Mme Helene’s Golden Hair Tonic” and “Mother Jones Bug Poison”.