1 hornblende family. It is semi-hard. It is rather brittle. It is rather difficultly frangible. Specific gravity, 2.991, 3.293, Kirvcan. 3.450, Br& son Chemical Chavactcvs. , 8re , or Constituent Paris. Silica, - . 64.00 Magnesia, . . 2 0.00 Alumina, . . 2^0 Lime, . - - 9 30 Iron, - - , 4.00 100 Bcrgmann. Geognoslic Situation. It occurs m beds in gneiss, mica-slate, and talc-slate sometimes alone, sometimes accompanied with ores of different kinds, as galena, magnetic ironstone, copper- pyntes, and bl.ende. Small and irregular veins occa sional y occur in transition-trap, and minute portions in llcetz-trap rocks. Geographic Situation. It occurs at Eilan Reach in Glenelg, in Inverness- shire; ,n the parish of Sleat, in the isle of Skye- diffe rent places in the isle of Lewis. In Cornwall, as- in the neighbourhood of Redruth* On the Continent, it is not * Greenough.