User blog comment:Thailog/Ep. 207 "Depths" discussion/@comment-5020469-20120610014741/@comment-34954086-20120610114829

^but unfortunately, not your Magic. The most likely is probably Yellow Jasper with a Lepidolite core. But it's very unlikely that the composition of the amulet would actually have been meticulously debated by the creators. So "Yellow" is sufficient.