390 FHYSIOGUAPUV. CLASS H.- 



without the Tin-ore, in veins traversing greywacjce with 

 ores of lead, rhombohedral Quartz, Sec. 



3. It occurs almost in every one of the Saxon and Bohe- 

 mian tin-mines, as at Schlaggenwald, Zinnwald, Ehren- 

 friedersdorf, and Geyer ; also in many places in Cornwall. 

 It is thus likewise found in France. In the principality 

 of Anhalt it occurs in veins in grey wacke. In the island of 

 Rona, one of the Hebrides, it was discovered in a vein of 

 graphic granite in gneiss. It is found in Siberia, accom- 

 panying rhombohedral Emerald, and in the United States 

 of North 



I. TANTALUM-ORE. 

 1. PRISMATIC TANTALUM-OBE. 



Prismatic Tantalum-Qre. JAM. Syst. Vol. III. p. 147. 

 Man. p. 241. Columbite. PHILL. p. 269. Tantalit. 

 BREITH. Hoffm. H. B. IV. 2. S. 191. Tantalit. 

 HAUSM. I. S. 310. Tantalit. LEONH. S. 379. Tantale 

 oxidd HAUY. Tabl. comp. p. 120. Trait;*, 2de Ed. 

 T. IV. p. 387. 



Fundamental form. Scalene four-sided pyramid. 

 P = 145 8', 99 S', 91 9 12'. Vol. I. Fig. 9. LEONH. 



a : b : c = 1 : V 5-4545 : *J 1-1636. 



Simple forms. P oo ; P ; (?r + x) 5 = 46 5(X ; 



Pr 1 = 56 4V; r + QD ; Pr + oo. 

 Char, of Comb. Prismatic. 

 Combinations. 1. P GO. P r -f- oo. Pr -|- QD. 



Bodenmais, Bavaria. 

 2. P oo. P. ?r -1. (P+oo) 5 . Pr-f-x. 



Pr -f- oo. Bodenmais. 



Cleavage, ?r -f GO rather perfect, Pr -J- GO less dis- 

 tinct. Traces of P oo. Fracture imperfect 



