Experimental #54 is one variation of a new CFL reactive series Northstar is working on. This glass is both flame and color stable, and will present a teal blue/green in natural light and then shifts to a brilliant lavender in a CFL. Air content varies with this color. For best results, use a 2700K (kelvin) CFL bulb as well as using this glass in thicker applications. This glass contains a small amount of copper, use an oxidizing flame for best results.