Thank you for viewing. This is a dichroic glass (expansion coefficient 90) nugget. The diameter is approximately 1.7 to 1.89 centimeters. I think you can use it for various things, such as making hair ties or pendants. Some of them have small air bubbles. Please refrain from purchasing if you are concerned about this. If you would like to purchase multiple items, please let me know in advance. We will offer a discount depending on the quantity and relist them as a combined listing.