alumine fluatee alkaline, Haig; cryone, halloide, Heidinger.

This rare mineral is of a snow-white colour. It was originally brought by a missionary from Greenland to Copenhagen, where, from its resemblance to the common varieties of the sulphate of barytes, it lay neglected for many years. At length Abildgaard, attracted by its peculiar ponderosity, was induced to undertake its examination, in the course of which fluoric acid, hitherto known only as a component of fluor spar, presented itself along with alumine; but as a considerable residue remained unaccounted for, Klaproth repeated the investigation, and discovered the presence of thirty-six per cent. of soda.

Of the geognostic relations of this interesting mineral nothing was known till the late Sir Charles Giesecke visited the locality, which he found situated on the west coast of the peninsula, in a ford or arm of the sea, denominated Arksut, near a place called Ivikkaet, where it occurs in two contemporaneous beds disposed in gneiss, nearly parallel to each other, and at no great distance.

Fragments of cryolite obtained by cleavage are too often called crystals; but nothing of the kind has hitherto been observed. Its cleavage, however, is very distinct after being well soaked in water: it is threefold, two of these forming rectangular prisms with very smooth surfaces, while the third is at right angles to these, and rougher. Its great fusibility, for it yields even to the flame of a candle, suggested to Abildgaard the name of cryolite, taken from κρύος, ice, and λίθος, a stone, which it has always retained. It contains, according to—

| Component | Quantity | |-----------|----------| | Klaproth | 36 | | Soda | 32 | | Alumine | 23-5 | | Fluoric acid and water | 40-5 |

and possesses a specific gravity of 2·949.