Carnelian

In ancient times, as well as today, Carnelian was believed to help timid speakers become both eloquent and bold.  Ancient warriors wore Carnelian around their neck for courage and physical power to conquer their enemies. In Egypt it was worn by master architects to show their rank of builder, and alchemists of the Middle Ages used it as a boiling stone to activate the energy of other Chalcedonies.  As the first stone in the breastplate of the High Priest, it signified the blood of the martyrs and was once believed to prevent illness and the Plague.