206 



DESCRIPTIONS OF MINERALS. 



Bladite. A hydrous sodium-magnesium sulphate ; from the salt 

 mines of Ischl, and near Mendoza. 



Lmweite. A hydrous sodium magesium sulphate ; from Ischl. Con' 

 tains more sulphur trioxide than Blcedite. 



Isometric. 

 1. 



Boracite. — Magnesium Borate. 

 Cleavage octahedral ; but only 



Usual in cubes with only the 

 alternate angles replaced ; or 

 having all replaced, but four 

 of them different from the 

 other four. The crystals are 

 translucent and seldom more 

 than a quarter of an inch 

 through. Also massive. Color white or grayish ; sometimes 

 yellowish or greenish. Lustre vitreous. H. = 7 when in 

 crystals, but softer when massive. Gr.=2*97. Becomes 

 electric when heated, the opposite angles of the cube be- 

 coming of opposite poles. 



Composition. Mg 3 15 B 8 -fJMg Cl 2 = Boron trioxide 62-0, 

 magnesia 31*0, chlorine 7*0=100. B.B. fuses easily with in- 

 tumescence coloring the flame green. The fused globule 

 becomes crystalline on cooling. Dissolves in hydrochloric 

 acid, and moistened with cobalt nitrate turns pink on igni- 

 tion. 



Diff. Distinguished readily by its form, high hardness, 

 and pyro-electric properties. 



Obs. Boracite is found only with gypsum and common 

 salt. It occurs near Luneberg in Lower Saxony, and near 

 Kiel in the adjoining duchy of Holstein, also at Stassfurth, 

 Prussia. 



RJwdizite. Resembles boracite in its crystals, but tinges the blow- 

 pipe flame deep red. It is supposed to be a lime-boracite. Occurs 

 with the red tourmaline of Siberia. Ludicigite. A magnesium-iron 

 borate ; fibrous and dark green to black. 



Szaibelyite. A hydrous magnesium borate, from Southeastern 

 Hungary 



WarwicMte. In rhombic prisms of 93° to 94°, hair-brown to black 

 with sometimes a copper-red tinge. A magnesium- titanium borate ; 

 from granular limestone of Edenville, N. Y. 



Sussexite. A hydrous magnesium-manganese borate. Fibrous and 

 pearly. G=342. from Mine HilL Franklin Furnace, Sussex Co., N. J. 



Ritromacjnetite. Occurs in white deliquescent efflorescences, having 

 a bitter taste, associated with calcium nitrate, in limestone caverns. It 

 is used, like its associate, in the manufacture of saltpetre. 



Wagaerite. A magnesium fluo-phosphate, occurring in yellowish or 



