ORDER vin. PKISMATIC TANTALUM-OKE. 391 



conchoidal, uneven. Surface, Pr + oo vertically 



streaked. 

 Lustre imperfect metallic. Colour greyish- and 



brownish-black. Streak dark brownish-black, on 



the file a little shining. Opake. 

 Brittle. Hardness = 6-0. Sp. Gr. = 6 038. 



Compound Varieties. Massive : composition gra- 

 nular. 



OBSERVATIONS. 



1. The synonymes quoted above refer also to all those 

 minerals which have been hitherto indiscriminately desig- 

 nated by the names of Tantalite^ Columbite, Tantate ojcide, 

 &c; and which occur in other localities than Bodenmais 

 in Bavaria. Several of these varieties, however, differ 

 so much from those included in the general description, 

 that they cannot be all comprehended within one and the 

 same species. Our information in regard to their regular 

 fonns is still very defective ; it is not certain, whether the 

 variety from Skogbohle in the parish of Kimito in Finland, 

 possesses prismatic or hemi-prismatic forms. The colour of 

 this variety is brownish-black, the streak between hair- 

 brown and clove-brown, hardness = 6-0, and sp. gr. = 7*075. 

 Of another variety, having a degree of hardness = 6*0, and 

 a specific gravity between 7*8 and 8-0, the forms seem to 

 be hemi-prismatic. The Tantalite from Broddbo, which 

 agrees very nearly with that from Finbo, both in Sweden, 

 is described as having a black colour, brown streak, a speci- 

 fic gravity of 6-291, when purified as much as possible, and 

 other properties which coincide with those of prismatic 

 Tantalum-ore. It is probable that some of these varieties 

 will form in future, one, or even several species, distinct 

 from that to which the above description refers ; but it 

 would be impossible, from the little we know of their natu- 

 ral-historical properties, to decide whether these will be 

 comprehended within the genus Tantalum-ore, or whether 



