Fine Emeralds were believed to be good for the eyes and engravers used to use them to stare into when their eyes grew fatigued.
Opals bring wisdom and good fortune.
It was believed that they were pieces of Heaven that got knocked down during violent thunderstorms. The Vikings used pieces of Iolite to help them in their navigation. The Black Prince's Ruby in the British Crown Jewels is really a very fine natural Spinel. An Opal will cut glass just like a Diamond. Diamonds, Sapphires, Tourmalines, Zircons, and Spinels come in ALL colors.