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British Mineralogy
Elastic Bitumen, or Fossil Caout-chou
- Class 1. Combustibles.
- Order 1. Homogeneous.
- Gen. 1. Hydrogen*.
- Spec. 1. Bitumen.
- Gen. Char. Inflammable, easily converted into gas by calor. Forms water by combustion with oxygen gas.
- Spec. Char. Nearly pure, fœtid, not easily volatile.
- Syn.
- Elastic Bitumen. Hatchett in Linn Trans. v. 4. 146.
- Bitume élastique. Haüy, v. 3. 313.
- Mineral Cahoutchou. Kirwan, v. 2. 48.
- Elastisches erdpech. Karsten, 42.
- Cahoutchou fossile. Laméthérie, v. 2. 540.
This is a harder specimen than the former, and much about the density of common Caout-chou. It is somewhat remarkable for its peculiar conchoidal fracture, on the faces of which, when minutely examined, peculiar risings occur, bounded by curved lines crossing each other, and terminating in a kind of centre not unaptly resembling the fracture of Carbonate of Lime with a kind of curvilinear crystallization†; the cracks seem not at all guided by this. The elasticity is something like the former, as soon as it separates if we endeavour to stretch it out. It is externally of a blooming gray, and internally of an olive green colour. This is oozing more or less from different parts of the gangue, which is a mixture of Carbonate of Lime, Galena, &c. Some of the smaller particles have a reddish illinition in their flaws
- * Unknown in its pure state, unless as the softest and purest Bitumen.
- † I have already received a fine specimen of Carbonate of Lime from Mr. Hall of Arkendale, very expressive of this.
