Siegfried bathed in the blood of heals in g g healing the dragon he slew and thus became invulnerable; the blind emperor Theodosius recovered his sight when a grateful serpent laid a precious stone upon his eyes; Cadmus and his wife were turned into serpents to cure human ills.
The copper mineral malachite is often used as a semi precious stone in jewelry.
With the council of Athene, he threw a precious stone among them.
Originally, amethysts were also considered precious, but generous deposits of the purple gem found in Brazil made it available and affordable for the public, and it was no longer labeled a precious stone.
For the same cost as a small diamond, a large semi precious stone can be purchased.