Crystallized Sulphate of Lime, or Gypsum
- Class 2. Earths.
- Order 1. Homogeneous.
- Gen. 3. Lime.
- Spec. 6. Sulphate of Lime.
- Spec. Char. Lime combined with sulphuric acid.
- Broad foliated Gypsum. Kirw. v. 1. 123.
- Gips et Fraveneis. Emmerl. v. 1. 527. 540.
- Chaux sulfaté trapezienne. Haüy, v. P.2. 270.
- Natrum selenites. Linn. Syst. nat. v. 3. 91.
Is a variety from Bedfordshire, sent me by favour of the Rev. T. O. Marsh, showing a tendancy of the laminæ to separate and bend, which they will generally do in the longitudinal direction. Thus, a plate of gypsum will be found to break less readily in this direction, always bending before it breaks, and then generally ruggedly. In the other directions, it is either glassy or foliaceous. When these crystallizations spread like the lower figures, they are commonly called Lion’s paws. Crystallized selenites are the moon-stones of Gesner and Agricola. See Plott’s Oxfordshire, p. 81.