TABULAR VIEWS OF MINERAL SYSTEMS. 465 » . / Order II.—Fixed; not volatilisable except at a white heat. 1. Assume or preserve the metallic form, after roasting on charcoal while any thing is dissipated, and subsequent, fusion with borax. Lustre metallic. Native Copper. . Lustre non-metallic. Malachite. 2. Not reducible to the metallic state before the blow pipe on charcoal, either with or without borax. t Magnetic after roasting. Common Pyrites. Not magnetic after roasting. Blende. Class III..—Earthy Minerals. Order I.—Soluble with effervescence, either wholly, or in con siderable proj)oi tion, in cold and moderately dilute muriatic acid; yield to the knife. 1. Effervesce vigorously. Marl. 2. Effervesce very feebly in cold, but more vigorously in warm, muriatic acid. Carbonate of Magnesia. Order II. Fusible before the blowpipe. 1. Hardness equal or superior to that of quartz. Gar net. 2. Hardness superior to thut of common window-glass ; generally yield in some degree to the knife. Fel spar. 3. Yield to the knife ; and sometimes feebly scratch glass. Tremolite. 4. Yield easily to the knife, and sometimes to the nail. Heavy-spar. 5. Very soft; yield to the nail. Gypsum. Vol. II. Order III,
