Tin foil hat Tin foil hat A tin foil hat is a hat made from one or more sheets of aluminium foil, or a piece of conventional headgear lined with foil, worn in the belief or hope that it shields the brain from threats such as electromagnetic fields, mind control, and mind reading. The notion of wearing homemade headgear for such protection has become a popular stereotype and byword for paranoia, persecutory delusions, and belief in pseudoscience and conspiracy theories. Note that "tin foil" is a common misnomer for aluminium foil; packaging metal foil was formerly made out of tin before it was
Foil opal as 'foil opals' by jewelry collectors. Foil opal Foil opals are simulated opal gemstones that first came into vogue during the jewelry-making boom of the late-Victorian era. Across Europe and the United States, these faux gemstones joined their paste counterparts (simulated diamonds, emeralds, rubies and sapphires made from glass) as the need for jewelry outstripped both gemstone availability and nouveau middle-class budgets. The term 'foil' refers to an actual metal foil that was sometimes used to create reflection and sparkle behind milky glass or quartz faces. Though technically incorrect, other simulated opals with various types of sparkling inclusions or shiny