42 BEURRE DE MONTAGNE. 



Beurre de Mo^'tagne, Dufrenoy. 

 Mountain Butter. See Petroleum, 



Bezoar Minerals, J. Woodward. Stones 

 composed commonly of several crusts one 

 within another, and having the crusts close 

 and cohering without any internal cavity. 



Bicarbonate of Ammonia. Occurs in 

 3'ellowish to white crystals in the guano de- 

 posits on the coasts of Africa and Patagonia 

 and the Chinca Islands. H. 1*5. S.G. 1'45. 



Comp. NH40C2 + H = ammonia o2'91, 

 carbonic acid 55-69, water 11-40= ICO. 



BiLDSTEiN, Werner. See Ac4Almatolite. 



BiMSTEiN, German. See Pumicp:. 



Biotina, or BiOTiNE. The name given by 

 Monticelli to the Anorthite found by him 

 among the old lavas at Mount Vesuvius. It 

 is easily distinguished from other species 

 with which it is associated by its superior 

 brilliancy. Colour white or yellowish. 

 Transparent. Fracture vitreous, inclined to 

 conchoidal. Presents double refraction. 



i?J5 unchanged. 



Partly soluble in nitric acid. 



Name. In honour of M. Biot. 



BiEBRiTE. Oblique. Usually occurs 

 in stalactites and crusts investing other 

 minerals. Colour flesh- and rose-red. Lustre 

 vitreous. Translucent. Friable. Taste as- 

 tringent. 



Comp. (Co, Mg) S + 7 H. 



Analysis by Winkelhlech : 



Sulphuric acid . . . 29-05 

 Oxide of cobalt . . . 19-90 

 Magnesia .... 3-86 

 Water 46-83 



99-65 



BB imparts a blue colour to glass of borax. 



This mineral is found in the rubbish of old 



mines at Bieber (whence the name Biebrite) 



near Hanau ; at Leogang in Saltzburg, and 



at Tres Puntos, near Copiapo, in Chili. 



BiEGSAMBR Silberglanz. See Flexible 

 Silver ore. 



BiNNirE, Heusser. A mineral identical 

 with Enargite except in crystallization. It 

 occurs in longitudinally striated, right rhom- 

 bic prisms. Colour steel-grey to black. 

 Streak a little darker than Dufrenoy site. 

 Brittle. Fracture conchoidal. 



Locality. — Found with Dufrenoysite in 

 the Dolomite of Binnen Valley, in Valais. 



BroTlTE, Brooke &^ Miller, Dana, Greg 8f 

 Lettsom, Hausmann. Rhombic. Occurs 

 in six-sided tabular prisms, with a highly 

 perfect basal cleavage. Sectile ; thin lamiuie 



BISMUTH-OCHRE. 

 flexible and elastic. Sometimes white or 

 colourless, but generally dark-green or 

 brown or nearly black. Lustre vitreous. 

 Transparent to opaque. Streak uncoloured. 

 Optically uniaxial. H. 2-5 to 3. S.G. 2-7 

 to 3-1. 



Comp. (Mg, Fe, K)3 Si + (A1 F^e) Si. 

 Analysis of a black Mica from Pfitsch in 

 Tyrol, by F. Bukeisen .- 



Silica ..... 38-43 



Alumina 15-71 



Protoxide of iron . . . 13-04 

 Magnesia .... 17-28 



Potash 11-42 



Lime, manganese, and fluorine trace 

 Water 2-76 



99-64 



BB fuses with difficulty to a grey or black 

 glass. 



Biotite may be distinguished from biaxial 

 Mica by being completely decomposed by 

 concentrated sulphuric ac^d, leaving a resi- 

 due of pearly scales of silica. 



Localities. Inverness in Scotland ; Skye, 

 jig. 48 ; Vesuvius (see Meroxene). 



Name. After Professor Biot, who first 

 pointed out the optical differences between 

 various kinds of Mica. 



Brit. Mus., Ca;^e 32. 



BiROUSA. The Persian name for Turquois. 



Bismuth-blende, Phillips. See Euly- 



TINE. 



Bismuth-glance, Jameson. See Bis- 



MU THINE. 



Bismuth-nickel. See Grunauite. 



BiSMUTH-oCHRE, Jameson, Kirwan. 

 Crystalline form, according to Von Born, 

 that of cubes or quadrangular lamella. Oc- 

 curs massive or disseminated; pulverulent, 

 earthy. Colour straw-yellow, sometimes 

 passing into pale yellowish-grey and ash- 

 grey, or verging on apple-green. Lustre 

 glimmering, dull in- earthy specimens. 

 Opaque. Easily frangible. Fracture small- 

 grained, uneven or earthy. S.G. 4-36. 



Comp. Bi = oxygen 10-35, bismuth 89-65, 

 = 100, with iron and other impurities. 



Analysis by Lampadius : 



Oxide of bismuth . . .86-4 



„ „ iron , . .5-1 



Carbonic acid , . .4-1 



Water 3-4 



99-0 



