
| 1. Can be scratched easily with a fingernail. | Sulfur: 1-1.5 Talc: 1 |
| 2. Can be scratched with a fingernail | Amber: 2-3 Ivory: 2-4 |
| 3. Can be scratched with a coin | Pearl:
3-4 Coral: 3-4 Malachite: 3.5-4 |
| 4. Can be scratched easily with the knife; cannot scratch glass | Rhodochrosite: 4 |
| 5. Can be scratched with a knife; can just scratch glass | Lapis Lazuli: 5-6 Turquoise: 5-6 Opal: 5.5-6.5 |
| 6. Can be scratched with a steel file; easily scratches window/bottle glass | Moonstone: 6-6.5 Tanzanite: 6.5-7 Peridot: 6.5-7 Zircon: 6.5-7.5 |
| 7. Easily scratches metal, glass and softer stones | Citrine: 7 Amethyst: 7 Tourmaline: 7-7.5 Garnet: 7-7.5 Emerald: 7.5-8 |
| 8. Scratches quartz and softer stones | Topaz: 8 Alexandrite: 8.5 |
| 9. Scratches topaz and softer stones | Ruby: 9 Sapphire: 9 |
| 10. Scratches Ruby | Diamond: 10 |
