Stunning vintage amethyst ring set in 14K gold

This is a stand out piece from a friend's collection, with a deeply hued oval amethyst of 10X7 mm framed in swirling gold. It is a size 6-3/4. Marked ISJC, which I think was the mark of a Canadian company specializing in jewelry crafted in precious metals. There is also a K mark for the gold purity, which is unclear, but I have had the ring tested, and have the jeweller's report showing it is 14K solid gold. This ring is in great condition - there may be minute scratches on the amethyst but they are not perceptible without magnification. (s)