My spectrometer is finally operating properly. again. I am still learning about color analysis, but I should have a new report up on this site, that compares color caused by copper as a chromophore and other chromophores. The focus will be on five color matched pairs of cuprian and non cuprian gemstones and differences in their chroma, a measure of the purity of a gemstones color. The report should be posted soon, so please stop back if you’re interested in the fascinating subject of copper in tourmaline.