ACTIVA-Lumina Polymer Air Dry Clay. Lumina Clay is an air-dry polymer resin clay that does not require heat to cure. When dried Lumina clay is waterproof; extremely durable; has a high flexibility; is acid free and is translucent. It is great for rubber-stamping; figurines; making flowers; ornaments; jewelry and so much more. This package contains one 5.25oz/150g block. Clay conforms to ASTM D4236. Imported.