Frost is described as a " transparent blue"
Testers reported "Frost is an aqua but it behaves a lot better than Effetre and Vetrofond aquas in that it doesn’t pit and boil at the drop of a hat. I found that the longer I worked Frost, and the more I cooled and reheated it, a few tiny scummy surface bubbles appeared but it was nothing I couldn’t remove. I think the key is to maintain an even heat and then it works like a dream. The Frost is more saturated than Effetre Pale Aqua 038 and, in my opinion, a smidge greener"