Fibrous Tourmaline Enlarge
July. 1. 1813 published by Jas Sowerby London.
British Mineralogy
CCCCLXXXIII
Argilla electrica

Fibrous Tourmaline

  • Class 2. Earths.
  • Ord. 1. Homogeneous.
  • Gen. 1. Argilla.
  • Spec. . Electrica.
  • Var. Fibrous.

The occurrence of capillary crystals of Schorle or Tourmaline in Unanimity mine in Cornwall, and the novelty of its appearance, warranted a figure of it as a variety in this work; and I am pleased with the friendly means by which I am enabled to give it, having been presented with the Specimen by William Rashleigh, esq, M. P., who succeeds to the valuable collection of my late friend, Philip Rashleigh, esq.

The crystals appear, from such as could be distinguished by the microscope, to be all hexaëdral prisms, rather flattest on two opposite sides: the whitish and grayish appearance is a dilute colouring in the crystals, which, when viewed perpendicularly, have often a rich dark blue aspect; they cover Quartz with Killas and Tin Ore.

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