It used to be used a lot in plumbing. It also used to be used to make white paint. That idea later started people making transistors out of other minerals and that started people making computers. Mica from central Colorado. Big sheets of Mica used to be used for windows and little sheets of Mica were used for tiny windows in wood and coal burning stoves.
Mica forms in very thin layers and can be peeled apart.
Those layers can hold a lot of water. If you look at the soil around potted plants, you may see little sparkling flakes of Mica. Aragonite from Aragon, Spain. Aragonite is a form of calcite which is very similar to what shells are made of. Shells from the coast of Maine.