海月（学名：Placuna placenta），中国大陆称作海月，台湾称作云母蛤，是莺蛤目云母蛤科云母蛤属的一种。

海月贝壳近似圆形，扁平，薄而透明；放射肋和同心生长线极细密；壳面为白色，微紫色壳顶，壳内面白色，有云母光泽。

The windowpane oyster (Placuna placenta) is a bivalve marine mollusk in the family of Placunidae. They are edible, but valued more for the shells and pearls. The shells have been used for thousands of years as a glass substitute because of their durability and translucence. More recently they have been used in the manufacture of decorative items like chandeliers and lampshades. In this use the shell is known as capiz. Shells are also used as raw materials for glue, chalk, and varnish.