Automolite

This substance was analyzed by Ekeberg. It is always in regular octaëdrons, either single or mackled, or transposed, as Haüy calls them; the fracture is foliated with the faces of the octaëdron, vitreous, and rather splintery contrarywise; fractures but little shining, and the whole nearly opaque, dark greenish; not fusible by the blowpipe; melts with borax into a greenish glass, which when cold is transparent.

The various points of sight this substance may be placed in, when many crystals are in one matrix, made me give the two views in the geometrical outlines. I do not know of any other variety in the crystals. They at first sight much resemble the octaëdral iron, fer oxidulé of Haüy.^* They have also been found partly covered with the greenish talc, in which they are found like the fer oxidulé, which is often of the same size. Whether these substances have undergone any change in their constituent parts, while inclosed in this talcose substance, so that alumine and zinc should take place of iron, and therefore make the distinguishing chemical difference, may be a question. As there no doubt exist secondary crystals, so may they not sometimes be detected more or less confirmed as such, while undergoing new infiltrations? Spec. Grav. 4.261.