BARYTES. 



tion. Sometimes fetid wlien rubbed. H. 

 2-5 to 3-5. S.G. 4-3 to 4-7. 



Fig. 41. 



Fig. 42. 



Fig. 43. 



Comp. Ba is. = siTlpburic acid •24-33, ba- 

 ryta 65-67; but. part of the baryta is fre- 

 quently replaced by strontia, and oxide of 

 iron, silica, carbonate of lime and alumina 

 occur sometimes as impurities. 



BB decrepitates violently, and melts with 

 great difficulty or only at the edges, impart- 

 ing a yellowish-green colour to the flame. 

 In the inner flame reduced to a sulphide, 

 which when moistened, smells slightly he- 

 patic. Not acted on by acids. 



May be distinguished from Strontia by 

 not tinging the flame red when tested with 

 muriatic acid and alcohol. 



Localities. — British. The finest crystallized 

 specimens found in the United Kingdom 

 have been procured from Dufton in Cumber- 

 land, see Jig. 41. Very large and perfect de- 

 tached crystals occur in the mud at the 

 bottom of a cave at Silverband near Dufton ; 

 one of them has been found Aveighing 1 cwt. 

 Fine translucent dagger-shaped crystals of 

 a yellowish -white tint occur at the iron 

 mines at Cleator moor in Cumberland ; Jig. 

 43. ' Figs. 42 and 43 represent Cornish forms. 

 Other British localities are the Fullers' Earth 

 pits at Nuffield, near Reigate in Surrey ; 

 Leadhills in Lanarkshire, Jigs. 41 and 42 ; 

 Breidden Hills, Shropshire; Wotherton in 

 Derbyshire ; Co. Cork ; &c. — Foreign. Przi- 

 bram iind Mies in Bohemia ; Felsobanya and 

 Kremnitz in Hungary ; Freiberg, Marien- 

 berg, Clausthal ; Roya, and Raure, in Au- 

 vergne. 



Name. From iSafv^, heavy. 



Barytes is a very widely diflfused mineral, 

 and commonly occurs in beds or veins of 

 metalhc ores ; when associated with ores of 

 iron it exercises an injurious influence on 

 the process of smelting. It sometimes forms 

 veins in secondary limestone. 



The following have been described as sub- 

 species, though diftering only in appear- 

 ance : 1. Granular Heavy Spar : 2. Colum- 

 nar Heavy Spar : 3. Radiated Heavy Spar, 

 or Bolognese Stone : 4. Hepatite : 5. Cawk. 



The Avhite varieties of Barytes are ground, 

 after having been heated and thrown into 



BARYTOCALCITE. 37 



water, and used as a pigment, either alone 

 or mixed with Avhite-lead. It has, also, late- 

 ly been proposed to employ Baiytes in sugar- 

 refining. Most of its " salts are highly 

 poisonous. The nitrate is used in pyro- 

 techny for making green Jire, in the folloAV- 

 ing proportion : Nitrate of Bars'tes 77, 

 Flowers of Sulphur 13, Chlorate of Potash 

 5, Metallic Arsenic 2, Charcoal 3. In the 

 year 1847, 10,320 tons of Barytes, worth 

 "about 11. per ton, for grinding, were raised 

 in the United Kingdom, principally in 

 Shropshire and Derbyshire. 



Brit. Mus.. Case 52. 



M.P.G. The largest crystal of Barytes 

 ever found in the United Kingdom is placed 

 on the floor at the S.E. end'of the Horse- 

 shoe Case. It weighs lOOlbs. See also Horse- 

 shoe Case Nos. 241 to 254. 



Barytine, Beudant. See Barytes. 



BARYTOCALCITE, Brooke. Oblique. Pri» 

 mary form an oblique rhombic prism. 

 Occurs massive and crystallized. White, 

 yellowish, greyish or greenish. Transpa- 

 rent or translucent, with a vitreous lustre 

 inclining to resinous. Streak white. Brit- 

 tle. Fracture imperfect conchoidal. H. 4. 

 S.G. 3-6 to 3-7. 



Fig. 44. 





Fig. 45 



I Com/). Ba C + CaC = carbonate of bary- 

 1 ta 66-3, carbonate of lime 33-7 = 100-0. 

 I Analyses ; a. by Children, h. by Delesse : 

 I a, h. 



I Carbonate of baryta 65-9 66-20 



Carbonate of lime . 33-6 31-89 

 Silica . . . „ 0-27 



99-5 98-36 

 BB infusible alone, becomes cloudy, and 

 gives a yellowish-green colour to the flame. 

 With borax fuses to a transparent glass, in 

 the oxi(iating flame of a pale amethystine 

 tinge, which becomes colourless in the inner 

 flame. 



Soluble with effervescence in muriatic 

 acid. 



Localities. It occurs plentifulh% both cry- 

 stallized and massive, in veins in ISIountain 

 Limestone, at Bleagill, Alston Moor, Cum- 

 berland. The crystals are greyish-white, 

 and semi-transparent. Sometimes crystals 

 two inches long are met yni'h., but in gene- 

 d3 



