What is isinglass?

Isinglass, which is called so because of its glass-like translucency, refers to thin sheets of mica. It’s used as peepholes in boilers and lanterns. It was preferred over glass because it would not splinter on breaking due to extreme temperature gradients. The name also applies to a collagen derived from the swim bladders of fish, especially the Beluga Sturgeon, used for making desserts and in the clarification of wines and beers. Isinglass is also the name of a famous British thoroughbred racehorse that won an English Triple Crown. A river in New Hampshire, USA, is named Isinglass because its water sparkles owing to the mica content in its riverbed. Project Isinglass was the code name for a highly secretive, air-launched aircraft the CIA studied in the 1960s. Later, with the advance of satellite technology, this technology was abandoned.