BOTRYOLITE. 



whence its name from /SoV^u?, a grape. Col- 

 our deep hyacinth -red, passing into ochre- 

 yellow in massive varieties. Lustre vitreous. 

 Translucent. Streak ochre-yellow. Taste 

 slightly astringent. H. 2-25 to 2-5. S.G. 

 2-04. 



Fig. 59. 



FeS S2 + 3 #-'e 82 + 36 H = sulphate 

 of protoxide of iron 19-0, sulphate of per- 

 oxide of iron 48o, water 82-7 = 100-0. 



Becomes covered with a dirty yellow 

 powder when exposed to a moist atmo- 

 sphere, but remains unaltered if kept dry. 

 BB intumesces and gives oflf water, leav- 

 ing a reddish-yellow earth. 



Partly soluble in boiling water, leav- 

 ing an ochreous residue. 



Locality. The Mellanrumsort level in the 

 great copper mine of Fahlun in Sweden, 

 forming a coating on Gypsum or Pyrites. 



Brit. Mus., Case 55. 



BoTRYOLiTE, Hausmanti. A variety of 

 Datholite occuring in mammillary concre- 

 tions, formed of concentric layers, having a 

 splintery or fibrous texture. Colour ex- 

 ternally pearl - or yellowish-grey ; internally 

 white, greyish and red in concentric circles. 

 Translucent at the edges. Brittle. It dif- 

 fers from Datholite in containing two atoms 

 of water instead of one. 



Comp. Ca B + Ca si + 2 H. 



Analysis by Rammelsherg ; 



Lime . . . . . 84-27 



Silica 86-39 ' 



Boracic acid . . . 18-34 



Water 10-22 



Alumina and peroxide of iron 0-78 



100-00 



BB melts into a white glass. 



Locality. Arendal in Norway, in gneiss, 

 accompanied by Schorl, Magnetic Iron ore 

 and Iron Pyrites. 



Name. From /SoV^u,-, a grape, and A./0O?, 

 stone ; from its occurring sometimes in small 

 botryoidal masses, which are white and have 

 an earthv texture. 



Brit. Mus., Case 39. 



Bottle Stone of Moravia. A kind of 

 Chrysolite of a dirty green and greyish- 

 green colour, found in flat pieces abovit an 

 inch in size. 



BOURXONITE. 51 



BouLANGERiTE, Thaulow. Generally oc- 

 curs massive, in plumose masses which ex- 

 hibit a crystalline structure when fractured ; 

 also granular and compact. Colour bluish, 

 lead-grey, often covered with yellow spots 

 from oxidation. Lustre metallic. H. 2o 

 to 8. S.G. 5-75 to 6., 



Comp. Pb S -f I Sb2 S3 = sulphur 17-9, an- 

 timony 24-1, lead 58-0 = 100. 



Analysis from Molieres, by Boulanger : 



Sulphur 18-5 



Antimony . . . .25-5 



Lead 58-9 



Iron 1-2 ■ 



Copper 0-9 



100-0 



BB fuses readily, giving off sulphurous 

 acid, and fumes of oxide of antimony ; oa 

 charcoal the presence of lead is indicated by 

 a yellow circle. 



Localities. Abundantlj'at Molieres (Gard) 

 in France ; Nasafjeld in Lapland ; Wolfs- 

 berg; massive, acicular, and fibrous near 

 Bottino in Tuscany. 



Name. After M. Boulanger, Engineer. 



Brit. Mus., Case 11. 



M. P. G. Principal Floor, Wall-case 21. 



BouRNONlTE, Jameson, Phillips, Nicol. 

 Rhombic: occurs crj-stallized in a right 

 rhomboidal prism (the priraar}"- form) vari- 

 ously modified. Crystals often cruciform ; 

 also massive, granular, and compact. Colour 

 and streak steel-grey, inclining to dull lead- 

 grey with a tinge of black. Opaque. Frac- 

 ture uneven, or flat conchoidal, with a bril- 

 liant metallic lustre. Brittle ; vields to the 

 pressure of the nail. H. 2-5 to" 3. S.G. 5-7 

 to 5-9. 



Fig. 60. 



Fig. 61. 



Comp. Pb* Sb + Cu2 Sb. 



Analysis from Wolfsberg bv Rammelsherg . 

 Sulphur . . .' . 19-76 

 Antimonv .... 24-34 



E 2 



