BROMIC SILVEE. 

 lustre. Crystals striated vertically. Streak 

 bright green. Bi-ittle, Fracture conchoidal 

 scarcely observable. IT, 3-5 to 4. S.G. 3-8 to 

 3-9. 



Comp. Cu S + oCuH = Cu4 S IP = sul- 

 phuric acid 17-7, protoxide of copper 70-3, 

 water 12-0 = 100. 



Analysis by Magnus, from Kezbanya : 

 Sulphuric acid . . . 17*13 

 Protoxide of copper . . 62-62 

 Oxide of zinc . . . 8-18 

 Oxide of lead . . . 0-03 

 Water . . . .11-88 



99-85 



BB on charcoaly fuses and yields a bead of 

 copper. 



Localities. Associated -with Malachite and 

 Native Copper at Ekatherinenburg, in Sibe- 

 ria. Nassau. Also in small brilliant cry- 

 stals on a white quartzose rock, associated 

 Avith fibrous Malachite, at Roughtea Gill, 

 in Cumberland. 



Named by Levy after Brochant de Villiers, 

 the French Mineralogist. 



Brit. Mus., Case 28. 



Bromic Silver. \ See Bromy- 



Bromite, Haidinger. J RITE. 



Bromlite. The name given by Thomson 

 to Alstonite. It occurs at Brownky Hill 

 mine near Alston, Avhich appears to have 

 been mistaken for Bromley Hill. 



Bromsilber. } See Bromtr- 



BrOMURE D'ArGENT. j ITE. 



Bromyr'ite. Cubical: in cubo-octahe- 

 drons. Colour, when pure, bright yellow, 

 with a slightly greenish tinge; often grass- 

 green or olive-green externally. Lustre 

 splendent. Sectile. H. 1 to 2. S.G. 5-8 to 6. 



Comp. Bromide of silver orAgBr = bro- 

 mine 42*6, silver 57'4 = 100. 



BB fuses easily. 



Imperfectly soluble in acids : soluble in 

 heated concentrated Ammonia. 



Localities. Accompanying other silver-ores 

 in Mexico, in the district of Plateros, and at 

 the mine of San Onofre, seventeen leagues 

 from Zacatecas-; also at Chanarcil!o,inChili, 

 with Chloride of Silver; and with Horn 

 Silver, at Huelgoet, in Brittany. 



Brit. Mus., Case 59. 



Brongniardite, Damour. A mineral near 

 Schilfglaserz {Dufrenoy). Lustre metallic. 

 Streak greyish-black. Fracture uneven. 

 H. scratches Calc-spar, and yields to the 

 knife. S.G. 5.95. 



Comp. PbS + Ag S + Sb2 S^ or (Pb, Ag) S 

 + iSb2 S3 = sulphur 190, antimony 30-7, 

 silver 25-7, lead 24-6 = 100. 



BROOKITE 





nalysis by Damour : 





Sulphur 



. 19-14 



Antimony . 



. 29-75 



Silver . 



. 24-81 



Lead . 



. 24-94 



(Jopper 



. 0-70 



Iron 



. 0*22 



Zinc . 



. 0-37 



55 



99-93 



BB on charcoal decrepitates, fuses easily, 

 giving off sulphurous odours and white 

 vapours; after roasting, yields a globule 

 of silver, surrounded with a yellow areola of 

 lead. 



Locality. The mines of Mexico, with Iron 

 Pyrites. 



Name. After M. Brongniart. 



Brongniartin, Von Leonhard. See 

 Glauberite. 



Bronzite : a variety of Diallage. Ob- 

 lique ; isomorphous with Augite : primary 

 form an oblique four-sided prism with a very 

 distinct cleavage parallel to the lateral 

 planes. Colour greenish-brown, brown, or 

 ash-grey, with a pseudo-metallic lustre, fre- 

 quently approaching that of bronze. Struc- 

 ture lamellar. Surface striated. Opaque 

 in mass, tran&lucent in thin laminse. H. 5-5. 

 S.G. 3-4. 



Analysis from Ultenthal by Regnault : 



Silica 55-84 



Magnesia .... 30*37 

 Protoxide of iron . . ' . 10-78 

 Alumina .... 1*09 

 Water . . . . .1-80 



99-93 



BB melts with great difficulty. 



Is not acted upon by acids. 



Localities. In crystalline masses imbedded 

 in serpentine, near Kraubat in Upper Sty- 

 ria ; very abundantly on Monte Bracco, near 

 Sestri, in Piedmont ; Baste in the Harz, im- 

 bedded in greenstone ; near Hoff in Bayreuth ; 

 Ulten-Thal, Tyrol ; also in Serpentine at 

 Coverack Cove, near the Lizai-d, in Corn- 

 wall ; in syenite at Glen Tilt, in Perthshire ; 

 in greenstone in the Isle of Skye; and 

 at Benenagh in Londonderry. 



Brit. Mus., Case 25. 



Brookite, Phillips, Beudant. Rhombic : 

 primary form a right rhombic prism. Occurs 

 in more or less translucent crvstals of a hair- 

 brown, yellowish, or reddish colour, with a 

 brilliant lustre inclining to metallic : the 

 opaque, iron black crystals with a sub- 

 metallic lustre from Arkansas have been 

 E 4 



