56 BEOSSITE. 



named by SKepard, Arkansite. Streak 3'el- 

 lowish-white. Brittle. H. 6 to 6-5. S.G. 

 4-12 to 4-17. 



Fig. 67. 



Comp. Ti or pure titanic acid, like Ana- 

 tase. 



Analysis, from the Urals, by Hermann : 

 Titanic acid . . . 9409 

 Peroxide of iron . . . 4-50 

 Alumina .... trace 

 Loss 1-41 



100-00 



BB alone on charcoal infusible, but with 

 salt of phosphorus is entirely soluble and 

 lorms a brownish-yellow glass. 



Insoluble in all acids except boiling oil of 

 vitriol. 



Localities. — British. Fine crystals have 

 been found near Tremadoc, in Caernarvon- 

 shire, in a vein of white Quartz at 

 Fronlen; in microscopic crystals imbedded 

 in Siderite at Virtuous Lady mine, Tavi- 

 stock ; and rarely in small crystals on tita- 

 nic iron, at Craig Cail leach, in Perthshire. 

 Foreign. Bourg d'Oisans in Dauphiny, 

 with Anatase and Crichtonite ; the Tete-noir 

 in Savoy ; the Urals, district of Slatoust, 

 and near Miask ; and in extremely minute 

 crystals at the Val del Bove, Etna, with 

 Eutile. This mineral was first observed by 

 Soret vof Geneva, accompanying Anatase 

 from Dauphiny, and described by Levy Avho 

 named it after Brooke, the crystallographer. 



Brit. Mus., Case 37. 



Bkossite. a name given to the Dolomite 

 of Traversella. 



Bkown Coal, is of more recent formation 

 than that associated with the true carboni- 

 lerous rocks, and is found in Miocene 

 tertiary strata. It generally occurs in 

 beds of comparatively small extent, but 

 often of great thickness, and is usually less 

 free from Pyrites than true Coal. Some- 

 times it retains much of the appearance of 

 the plants from which it is derived, and not 

 only shows distinctly the structure of the 

 wood, but retains its outward form al^-o ; 

 while sometimes it can scarcely be distin- 

 guished from ordinary coal, breaking with 

 a conchoidal fracture.' See Lignite, Sur- 



TURBRAND. 



BRUCITE. 



Brit. Mus., Case 60. 



M. P. G. Principal Floor, Wall-case 40, 

 (Jamaica) ; Horse-shoe Case, Nos. 84 to 87. 



Brown Hematite, the name given to 

 compact mammillary and stalactitic varie- 

 ties of Limonite. See Limonite. 



Brown Iron-cinder. See 1'itticite. 



Brown Iron- ore. See Limonite. 



Brown Lead-ore, Jameson, Kirwan. 

 See Pyromorphite. 



Brown Ochre includes the soft and 

 earthy, decomposed varieties of Limonite, or 

 Brown Iron-ore. 



Brown Quartz, Phillips. See Smoky 

 Quartz. 



Brown Spar. This name has been given 

 both to the brown crystallized varieties of 

 Dolomite, and especially to those varie- 

 ties which contain a percentage of carbon- 

 ate of iron. 



M.. P. G. Principal Floor, Wall-case 

 50 (British). 



Brucite. The name given by Cleaveland 

 to Chondodrite, in honour of Professor Bruce, 

 of New York. 



Brucite. Hexagonal. Usually foliated, 

 massive, or in fibres which are separable 

 and elastic (Nemalite). Colon.- white, in- 

 clining to grey, blue, or green. Lustre 

 pearly. Translucent, subtranslucent. Streak 

 white. Sectile, thin laminae flexible. H. 

 1-5. S.G. 2-35. 



Fig. 68. 



Comp. Hvdrate of magnesia, or Mg H = 

 magnesia 68-97, water 31-03 = 100. 



Analysis from Swinaness, by Thomson ; 

 Magnesia .... 66*67 

 Protoxide of manganese . 1-57 

 Protoxide of iron . . .1-18 



Lime 0-19 



Water 30-39 



100-00 



BB becomes opaque and friable, but does 

 not fuse. 



Entirely soluble in acids without efferves- 

 cence. 



Brucite accompanies other magnesian 

 minerals in Serpentine. 



Localities. Pyschminsk in the Urals; 

 Goujot in France ; Hoboken, N.J., opposite 

 the city of New York, in veins which are 

 sometimes an inch in width, rarely in minute 

 polished crystals as inj^^. 68 ; Wood's minC; 



