Ruby-red spinel with 400-year-old engravings, reportedly discovered near Leicestershire railway track, to go on sale For a few days in the 1920s, according to a cutting from a local paper in ...
MAGNESIUM aluminium oxide sure is a pretty mineral. It forms spinel, a gem coveted throughout history and whose red variant is sometimes confused with ruby. It was used in the Timur Ruby necklace made ...