I received these from a Ryukyu glass studio. They are glass fragments. Red: 144g Clear glass: 96g Green: 48g Light blue and blue: 429g Black: 355g Suitable for creating artwork using glass and other crafting activities. The cut edges are sharp. They are not polished like cullet. The glass colors have a transparent quality. Includes rare black glass. As you can see in the photos. Recycled boxes will be used for packaging. I will pack them to prevent further breakage. Thank you for your consideration.