Amethyst was a catalog color from 1942 to 1957, 1961, 1962 and 1991 to 2005.
Early Amethyst was a variable color. The 1991 to 2005 variation (shown above) has a slight brown tint when compared to the other purples and the coloration frequently appears slightly mottled.
BLOG UPDATE: November 22, 2013 The color formulations for Blenko’s Amethyst (and some additional colors, as well) appear to have been different each time it was added to the catalog. When Amethyst was added to the catalog in 2012 (and 2013) it had yet another formulation, so basically, there were at least 4 different colors called Amethyst. In addition, the color formulations were also changed midstream at times because the “formulation” was deemed to be too risky for the workers to be using.