JAMESONITE. 195 82. JAMESONITE.—Jamesonite ; Dufrenoy. Axotomer Antimon-Glanz; Mobs. Jamesonit; Hausmann, Haidinger. Prismatic. a 100 cleavage, c ooi cleavage, m no. FIG. 195. ac 90° 0 f me 90 o ma 50 40 mm' 78 40 Cleavage, c, very perfect; m, a less perfect. Opaque. Lustre metallic. Steel-grey. Streak the same. Sectile. h = 2 , o...2 - 5. g = 5-564...5-618. In the open tube and with acids the reactions are the same as those of zinckenite. Decrepitates when heated. Before the blowpipe melts easily, deposits a sublimate of oxides of lead and antimony on the charcoal, and, after the lead and antimony are driven off, leaves a slag which usually affords the reactions of copper and iron. With soda yields a globule of lead. t m Pb’Sb’, lead 48’59, antimony 38 - 2i, sulphur 20-20. Analyses of jamesonite a from Valencia d’Alcantara by Sehaffgotseh, b, c, d from Cornwall by II. Hose, e from Arany- Idka by Lowe:— < a b c d e Lead . . 39-97 40-75 40-35 38-71 39‘67 Iron . . 3-03 2 30 2-90 2 05 2 91 Copper. . — 0-13 o-2i 0-19 1-73 Zinc . . . 0-42 Fb,Fe,Zn 0‘74 Zn 0'34 Silver . . — — -— — 1-44 Bismuth . roo — — — 021 Antimony . 32-62 34-40 83'47 34-90 32'17 Sulphur . 21-78 22-15 undetermined 2563 18'07 In acicular crystals, parallel or diverging groups, more fre quently in fibrous masses. Is found in Cornwall sometimes with bournonite, at Valencia d’Alcantara in Estremadura, Arany-Idka in Hungary, Carcas- 8 ono and Pont Vieux in Erance, Nertschinsk in Siberia, Catta il ranca in the Brazils. . The substance called ‘ bleischimmer’ is supposed to be jamesonite. Opaque. Lustre metallic. Light lead-grey. Ac quires a blackish tarnish. Streak shining. Soft. Sectile. G =