METALLIFEROUS MINERALS. 219 FIIANKLINITE* Franklinite, Btithicr. Dodecahedral Iron Ore, M. Zinc Oxyde Ferri- fere, II. Siderite Zincifere, Necker. Combination of the peroxide of iron, with the oxide of zinc, and red oxide of manganese. > New Jersey. Peroxide of iron 66-0 66'10 68-86 Oxide of zinc 17-0 17-43 10-81 lied oxide of manganese 16-0 14-96 18-17 Berthier. Thomson. Abich. Sp. Gr. 5-0—5-1. H. = 6-0—6-5. Ihis mineral bears much resemblance tooxidulated iron. It oc curs in grains or in granular masses composed of imperfect crys tals, occasionally exhibiting the planes of the octahedron, and those replacing its edges, but bounded more often by the irregu lar faces produced by contact; the structure is lamellar, parallel to the planes of the regular octahedron ; brittle ; fracture con- choidal ; streak deep reddish-brown—distinguishing it from oxid- ulated iron, the streak of which is black. Acts slightly on the magnet; soluble without effervescence in heated muriatic acid. At a high temperature the zinc is driven off, and a hard compound of iron and manganese remains. Before the blowpipe with borax it forms a green glass, which when completely saturated becomes red, and on cooling assumes a greenish-brown colour, and remains transparent; with salt of phosphorus it yields a yellowish-grey glass, and with soda is insoluble. P on P 109° 25' P on e 144 40 The measurements by the reflective goniometer prove the regular octa hedron to be its primary form. It occurs in Sussex County, New Jersey, accompanying the red ox.de of zinc, and is frequently imbedded in calcareous spar, and associated with quartz, yellowish-green garnet, and other substances. It is also mentioned as accompanying ores of zinc, >n amorphous masses, at the mines of Altenberg near Aix-la- Chapelle. ° Franklinite, in honour of the celebrated Franklin.