Sulphate of Barytes
- Class 2. Earths.
- Order 1. Homogeneous.
- Gen. 6. Barytes.
- Spec. 2. Sulphate.
- Spec. Char. Combined with sulphuric acid.
- Baroselenite. Kirw. v. 1. 136.
- Schwer-spath. Emmerl. v. 1. 550.
- Baryte sulphatée. Haüy, v. 2. 295.
- Natrum cristatum. Linn. Syst. Nat. v. 3. 90.
Tabular sulphate of barytes is the most common variety. The finest specimens generally come from the neighbourhood of Cumberland.
The tabular crystals are sometimes transparent, and often more or less stained with ochre; they mostly stand upon their edges, often very distinct and in every direction. It may be observed that their edgs are parallel to the diagonal of the nucleus, therefore it becomes rectangular. The present specimen has small corner facets, parallel to the faces of the primitive nucleus. One end has bevelled faces on either side, the angles measuring about 128°, which are parallel to the small triangular facets on the lower figure of Tab. 70. The other has three bevellings. See the geometrical figure.