Mother of pearl which is also known as nacre is an iridescent substance that forms the lining of shells of some fresh and salt water molluscs such as mussels and oysters. It comes predominantly from the shell of the pearl oyster, freshwater pearl mussel and the abalone which is a type of gastropod or sea snail.
Mother of pearl is a material that's known to have been used at least as far back as 4200 B.C. During the 15th century it was widely used by Ottoman Turks in art but also to make Koran cases, writing desks and chests, shutters for windows and doors and in pulpits and lecterns. It was was also used in the architecture and for the decoration of mosques and palaces.
Pearl buttons were a major business in the early days of Illinois in the USA but it's not known exactly how early this industry began. What is known is that is was in progress during the early 1900's. America was exporting billions of tons of mother of pearl buttons all over the world up until World War II but the industry was then pretty much wiped out with the introduction of newly invented plastic.