This is for random pull velvet obsidian that has been tumbled and polished. Mexican Velvet Obsidian is a higher quality obsidian with loads of magnetite that create the velvet like pattern and flashes within! It often features many different colors, and it works into some truly amazing cabochons! It is a personal favorite of ours, and we have never been let down while cutting up batches of these! They can also make awesome pendants or can be great for wire wrapping projects! The color in velvet obsidian is light sensitive. In order to see it, you need to be under bright light, and the stone has to be turned correctly, similar to how a fire opal behaves.