What is Capiz?
According to Wikipedia, the windowpane oyster (Placuna placenta) is edible, but valued more for its shell 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.
Distribution extends from the shallows of the Gulf of Aden, around India, then Malaysia to the southern South China Sea, and around the Philippines, where it is abundant in the eponymous province of Capiz. They are found in muddy or sandy shores, in bays, coves, and lagoons to a depth of about 100 m (330 ft). In the Philippines, fisheries are regulated through permits, quotas, size limits, and protected habitats. The almost-flat shells of the capiz can grow to over 150 mm (5.9 in) in diameter, reaching maturity between 70 to 100 mm (2.8ot 3.9 in)