We have the ability to add glow pigment to any product that is primarily transparent glass and you can see through it. When you choose this option, you are buying yellow or blue/yellow pigment to be added to our protective glue fill in the back on a mini you are purchasing at the same time from our website. This is an add on option for customization. Please e-mail pyrohyzer@gmail.com with questions. We will be in touch confirming the order in no more than 5 business days (generally less). We do not fill previously purchased minis.