Precious Stones
The hardness of precious stones, beginning with the hardest, is as follows: 1. Diamond; 2. Ruby; 3. Sapphire; 4. Topaz; 5. Hyacinth; 6. Emerald; 7. Garnet; 8. Amethyst; 9. Agate; 10. Turquoise; 11. Opal.
Twelve hundred entries from the golden age of cast metal — how bells are founded, why brass is not bronze, what a cupola melts and a core withstands — by Simpson Bolland, the trade's great teacher.
The hardness of precious stones, beginning with the hardest, is as follows: 1. Diamond; 2. Ruby; 3. Sapphire; 4. Topaz; 5. Hyacinth; 6. Emerald; 7. Garnet; 8. Amethyst; 9. Agate; 10. Turquoise; 11. Opal.