| Of Hydrogen | Bitumen. |
| Coal. |
Bituminized wood is Lignite, which, when very compact, is Jet.
“Amber” is a vegetable resin. It is obtained from rivers in Sicily, and from mines in Russia.
| “Carbonates” of Lime | Limestone. |
| Calc-spar. | |
| Chalk. |
The “marbles” of Paros and Carrara are crystalline Limestone: those of Siena are compact Limestone.
Alumina comprises 2 species:—1. Corundum; 2. Sapphire.
1. “Corundum” is a very hard crystal, the common type of all the Sapphires.
2. Oriental “Sapphires.” These embrace 6 kinds.
- The blue Sapphire.
- ” red or “Ruby.”
- ” green or Emerald.
- ” purple or Amethyst.
- ” golden or Topaz.
- ” sea-green or Aquamarine.
These are pure Alumina.