 Mother @-@ of @-@ pearl or nacre is the naturally occurring lustrous layer that lines some mollusc shells . It is used to make pearl buttons and in artisan craftwork to make organic jewellery . It has traditionally been inlaid into furniture and boxes , particularly in China . It has been used to decorate musical instruments , watches , pistols , fans and other products . The import and export of goods made with nacre are controlled in many countries under the International Convention of Trade in Endangered Species of Wild Fauna and Flora . 
