Mother of Pearl
Mother of pearl is the common name for what is technically called nacre. Nacre is the iridescent material found on the inner shell of some mollusks, and is the substance used by oysters to make pearls.
Due to the strength and iridescent shine of mother of pearl, it is a popular construction material and finish for things like buttons, cufflinks and jewelry. For as long as people have been making clothing fasteners, mother of pearl has been used as a button making material on select garments. Because of the moderate cost associated with true mother of pearl it is not uncommon to find synthetic mother of pearl finishes on buttons used for inexpensive garments. From a medium to long distance these synthetic materials are indistinguishable from the real thing; however from a short distance it is easy to discern the difference between the natural and synthetic materials. Synthetic mother of pearl does not possess the same luster or depth of color as its natural counterpart.
True mother of pearl buttons degrade overtime if excessively placed in the washing machine due to the mechanical friction and cleaning chemicals they are exposed to; therefore it is advisable to hand wash or dry clean items that have genuine mother of pearl buttons. Though mother of pearl items are no longer as popular today as they were in the past it is still a widely used material in clothing and jewelry construction.