Opaline is a collaborative experiment between Northstar Glass and Gaffer Glass that has been discontinued due to workabitly issues in 2016. As a highly desired glass, Northstar recently produced the very last of the inventory available. This means that this is the last campaign available of the original Opaline formula. In an effort to push opacity we are discovering a shortened thermal elasticity. What this means to us in front of the torch is a sensitivity to heat application or loss. A shorter time between kiln and flame would be an example. Recommended annealing temperature of 1100f-1150f.