494 , molybdena. the department of the Rhone in France ; and in granitic rocks m the Alps and the Y'osges. ■Asia.—Siberia. America—Greenland. Observations. This mineral has frequently been confounded withgra- phite; but the following characters sufficiently distinguish them from one another: The colour of graphite is steel- grey. inclining more or less to iron-black ; whereas that of molybdena is lead-grey: if both minerals are rubbed on a piece of white porcelain, it will be seen that the streak made by the graphite is'of the same colour with the substance by which it was made ; while that made by the molybdena is greenish-grey: and graphite soils strongly, but molybdena only slightly. 2. Molybdena-Ochre. Molybdanocher, Karsten. Molybdanocher, Karsten, Tabel. s. 70. Id. Ilaus. Handb. b. b s. 336. External Characters. ' Its colour is sulphur yellow, which passes on the one side into straw yellow and orange yellow, and on the other into siskin green. It occurs disseminated, and incrusting molybdena. It is friable. 3 It is dull. Geographic Situation. It is found investing and intermixed with molybdena, in the granite of Corybuy at Loch Creran ; and also at Nummedalen in Norway. ORDER XVI-