W. P. Headden — Columbite and Tantalite. 91 



On the Newton lode it occurs very sparingly in thin plates, 

 associated with beryl, which occurs disseminated through the 

 granite in individual crystals from an inch to one and a half 

 inches in diameter and several inches in length. Both the 

 occurrence and the association of these minerals in the Newton 

 •lode are entirely different from that of the Etta mine. 



The only piece of columbite found at the Bob Ingersoll mine 

 has been described by Prof. W. P. Blake, who estimated its 

 original weight to be 2,000 pounds. At the time of my visit 

 to this locality only a small portion of this mass remained, it 

 having been broken to pieces and carried away or cached. I 

 obtained some smaller pieces, varying in weight up to thirty 

 pounds ; such a piece is now in the cabinet of the Dakota School 

 of Mines. The mineral occurs in small crystals, and sparingly 

 at the other localities which I have visited in the southern sec- 

 tion, and the same may be said of the northern section of the 

 Hills. 



No measurements have been made on any of the crystals, and 

 the description here given may need subsequent alteration. 

 Well terminated crystals are rare and usually small. The best 

 and indeed almost the only fair crystals obtained are from the 

 beryl which occurs in the Etta mine, but I have in one speci- 

 men, from an unknown locality, two clusters of several crystals 

 each, in which the crystals are well terminated. 



The crystals occurring in the Etta mine vary greatly in luster, 

 and also in their modifications. The usual form is tabular, the 

 crystals being sometimes two inches wide, two or more inches 

 long, and not exceeding one-quarter of an inch in thickness. 

 The terminations of such crystals are always poor. The sur- 

 faces recognized on such are : 010, 110, i30, 100, 132, 102, 

 001, 031. These forms are not recognizable on all of the crys- 

 tals ; sometimes the prism 130, and sometimes both prisms are 

 wanting. The crystals are often thinner at one edge than at the 

 other, and are otherwise distorted; they are sometimes vertically, 

 again irregularly, and even horizontally striated. The strise on 

 the Etta crystals do not appear to be due to polysynthetic crys- 

 tallization. The luster on the different surfaces is not equally 

 bright ; that of the macropinacoid is almost always shining, 

 while the basal pinacoid is very often dull, as though finely 

 etched. In color the duller crystals are of a grayish black ; the 

 brighter ones of a pure black. The streak is, when not other- 

 wise designated, a dark brown, a*nd the powder, grayish black. 

 The mineral from the Hills differs from specimens obtained 

 from other sources in two respects : in fracture, which is rather 

 fine-grained and quite dull in luster, while sub-conchoidal frac- 

 ture and iridescence on fractured surfaces are almost wholly 

 wanting. 



