Pearly Kings and Queens, known as pearlies, are an organised charitable tradition of working-class culture in London, England.
Henry Croft, the first Pearly King
This group of Pearly Kings and Queens were collecting for charity at London's Covent Garden.
Nacre, also known as mother of pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent.
The iridescent nacre inside a nautilus shell
Nacreous shell worked into a decorative object
Electron microscopy image of a fractured surface of nacre
Fossil nautiloid shell with original iridescent nacre in fossiliferous asphaltic limestone, Oklahoma. Dated to the late Middle Pennsylvanian, which makes it by far the oldest deposit in the world with aragonitic nacreous shelly fossils.