Northstar Unobtainium boro glass is a very dense gun metal blue with lots of sparkle. It is well suited for stringer application and blown work. It is easily worked and can take a lot of heat. To keep the color most vibrant, work in a neutral to slightly oxidizing flame. Try to avoid deep encasement, it may cause cracking. Please use NS-104 Unobtainium with care and test your application before making expensive pieces. Outside work seems to work just great with no problems. Try coating NS-104 Unobtainium with NS-86 Garnet or NS-88 Pomegranate to achieve a brilliant ruby sparkle. Any transparent color coated over NS-104 Unobtainium looks great.