Like all kinds of other African steel beads, Baule beads are Solid using the misplaced wax technique, and sometimes characteristic Sunlight and moon patterns.  Swarovski crystal is greatly considered to be the best optically pure guide crystal out there. From the late 1800’s Daniel Swarovski patented a crystal slicing device https://stephenspkgb.answerblogs.com/31564422/5-easy-facts-about-pink-beaded-bracelet-described