mother-of-pearl
n [U] (also nacre) hard smooth shiny rainbow-coloured substance that forms the lining of some shells (eg oysters, mussels) and is used for making buttons, ornaments, etc 珠母层; 珍珠母
[attrib 作定语]
a mother-of-pearl ear-ring, necklace, brooch, etc 珠母耳环、 项链、 饰针等.