Thank you for viewing! This is a dichroic glass (expansion coefficient 90) nugget. It's a large nugget, approximately 2 centimeters in diameter. I think it can be used in various ways, such as making hair ties or pendants. Some pieces have small air bubbles inside. Please refrain from purchasing if you are concerned about this. If you would like to purchase multiple pieces, please let me know in advance. I will offer a discount depending on the quantity and relist them as a combined listing.