YTTKO TAXTALITE. 173 



It occurs at Finbo ancl Broddbo, near Fahlun hi Sweden, 

 along with Albite and rhombohedral Emerald, and is im- 

 bedded in rhombohedral Quartz. 



YTTRO-TANTALITE. 

 ORE. 



Yttro-Tantalite. JAM. Syst. Vol. III. p. 177- Yttro- 

 columbite. PHILL. p. 271. 



L Black Yttro-tantalite. 



Indistinct traces of crystallisation. Fracture lamel- 

 lar in one direction, coarse granular in another. 

 Disseminated, seldom of the size of a hazel nut. 



Imperfect metallic lustre. Opake. Colour black. 

 Streak grey. 



Brittle. Scratches glass. Sp. Gr. = 5-395, BER- 



ZELICS. 



ii. Yellow Yttro-tantaHte. 



No trace of crystallisation. It is found between 

 felspar in the state of lamellae, seldom in grains 

 not exceeding the size of a pepper corn. The 

 longitudinal fracture of the lamellae is foliated, 

 the cross fracture fine grained. 



Lustre resinous on the surface, vitreous in the 

 fracture. Colour yellowish-brown, accidentally 

 with green spots or stripes. Streak white . . . opake. 



Scratches glass with difficulty, but is very distinctly 

 scratched by it. Sp. Gr. = 5-882, ECKEBERG. 



iii. Dark Yttro-tantalite. 



No trace of crystallisation. Occurs with the pre- 

 ceding, commonly in thin laminae, seldom in 



