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I do hot know that this crystallized variety of magnetic iron 

 ore has been observed in Great Britain before. Dr. Badham 

 gave me a fine octaedron of the Swedish sort, from Fahlun 

 (where such specimens are not rare), which is above half 

 an inch in diameter : but this is not more strongly attracted 

 by the magnet. It is coated with mica, and, within, is of 

 a more or less deep-brown red, as are ours, sometimes ap- 

 proaching steel-gray and black, partly shining, and metallic. 

 Fracture uneven, somewhat earthy. The crystals are ar- 

 ranged in convenient order, to see the additions that assist 

 in, modifying the different crystallizations, (viz.) 



The upper figure on the right hand exhibits the regular 

 octaedron, the faces of which, by the addition of the la- 

 minae of superposition, or superior coating, form long six- 

 sided facets, which are those of the dodecaedron with eight 

 triangular faces parallel to those of the octaedron, see the 

 middle figure. These are the nearest approach we have seen 

 to the octaedron in our specimens ; with more laminae, 

 it keeps the same form which is shown, but with smaller tri- 

 angular facets in the left hand figure and the right-hand lower 

 figure. In the lower figure on the left hand the laminae have 

 advanced so far as to form the complete rhomboidal dode- 

 caedron. The geometrical outline shows this manner of 

 casing over each other ; but we must beg our readers to 

 substitute the octaedron in lieu of the dodecaedron in the 

 centre, as we find is the case upon further examination 

 since the engraving: was finished. 



