Sapphire.
| Grains. | ||
|---|---|---|
| Or, | Paste | 4608 |
| Oxide of cobalt | 68 | |
This mixture should be carefully fused in a luted Hessian crucible, and be left 30 hours in the fire.
Amethyst.
| Grains. | ||
| Paste | 4608 | |
| Oxide of manganese | 36 | |
| Oxide of cobalt | 24 | |
| Purple of Cassius | 1 | |
Syrian Garnet, or Antient Carbuncle.
| Grains. | ||
| Paste | 512 | |
| Glass of Antimony | 256 | |
| Cassius purple | 2 | |
| Oxide of manganese | 2 | |
Beryl, or Aqua Marina.
| Grains. | ||
| Paste | 3456 | |
| Glass of antimony | 24 | |
| Oxide of cobalt | 11⁄2 | |
In all these mixtures, the substances should be mixed by sifting, fused very carefully, and cooled very slowly, after having been left in the fire from 24 to 30 hours.