Spinellane Enlarge
[Undated]
Exotic Mineralogy
XCIV
Spinellane

  • Syn. Spinellane. Nose Etudes Mineralogiques, p. 109. Haüy Tabl. 66.

We know but little more respecting this inconspicuous mineral than what is related of it by Nose and Haüy: it it sufficiently distinguished from Spinelle, with which

Nose compared it, by its inferior hardness, as it may be scratched by a knife, and easy fusibility into a white frothy enamel. Haüy describes the nucleus to be an obtuse rhomboid, whose faces measure upon each other 117°23′ and 62°37′, which is divisible into six tetrahedrons, by planes parallel to the lateral edges; its crystals being six-sided prisms, terminated by three-sided pyramids, with truncated edges, have much the appearance of dodecahedrons, with rhomboidal planes and truncations parallel to the faces of cubes; but Haüy has observed a difference of about two degrees in the measure: the faces upon the edges of the pyramid are the primitive ones, the faces of the pyramid being analogous to those of the cube. The structure Haüy has observed, is nearer that of Garnet than of Spinelle; and it is to be remembered that Haüy gives his measures with some degree of doubt. Spinellane has hitherto been found only upon the borders of the lake of Laach, in the department of the Rhine and Moselle, in imperfect crystals dispersed among white semitransparent almost tabular crystals of Feldspar, loosely aggregated together, and accompanied by Magnetic Oxide of Iron: Haüy mentions also Quartz, Horn blende and black Mica.

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