Complex sentence: Placunidae are extensively collected in the Indo-West Pacific, and cultivated in several areas, for their translucent shell, originally as a substitute of glass in glazing, now mainly for the manufacture of trays, lamp-shades and numerous decorative items.
Split into simpler sentences: Placunidae are extensively collected in the Indo-West Pacific, and cultivated in several areas, for their translucent shell. The shells were originally used as a substitute for glass in glazing, but are now mainly used for the manufacture of trays, lamp-shades and numerous decorative items.