46 Graham — Native Gold from Gold Harbour. 



The form exhibited by the crystals is not at first sight obvi- 

 ous; the most striking feature of the habit is the arrangement 

 ol a number of almost square, four-faced pyramids, which lie 

 very nearly, though not quite, in zones encircling the crystal. 

 Parallel to the bases of these the faces are heavily striated, and 

 in a great many cases there is a step-like structure; the occur- 

 rence of the accompanying reentrant angles at the junction of 

 neighboring pyramids causes these to stand out from one 

 another more prominently, and is largely responsible for the 

 pronounced "pyramidal" appearance. 



From an inspection of the striae it is easily possible to l5cate 

 the various axes of symmetry and orientate the crystals ; meas- 

 urement of the large crystal on the telescope goniometer showed 

 it to possess all the faces of the six-faced octahedron { 4-21 J- , 

 uncombined with any other form. The smaller crystals were 

 not measured, but they are similar, so far as can be seen with- 

 out removing them from the specimen ; one was noticed which 

 bore small faces of the dodecahedron, replacing the summits 

 of the " four-faced pyramids" referred to above, and also of the 

 cube. The general habit of the crystals is shown in the figure. 



From the nature and distribution of the reentrant angles, it 

 was at first thought that the crystals might possibly be twinned, 

 in which case they would have to be regarded as supplement- 

 ary twins of some hemihedral form, such as the pentagonal 

 icositetrahedron. As is well known, the holohedral symmetry 

 of gold has been called in question by Hehnhacker* and K. 

 Marti]], f who have described apparently tetrahedral forms of 

 this substance : but, apart from this, it has been found that the 

 crystals, however much distorted and misshapen, can always 

 be referred to some form or combination of the holohedral class 

 of the cubic system, and this is generally accepted as being the 

 true symmetry of gold. 



Although the evidence furnished by the reentrant angles 

 in the present crystals is suggestive, it is not, in itself, strong 

 enough to warrant the assumption that they are hemihedral 

 and twinned. Prof. E. S. Dana has very kindly examined the 

 specimen, and is of opinion that the striae and reentrant angles 

 are best to be regarded as the result, only, of an oscillatory 

 repetition of the faces of the normal six-faced octahedron. 



The specimen was collected by Mr. John McLennan, A.E.S.M., 

 of Skidegate, from a quartz vein on his claim at Gold Harbour, 

 and Mr. Robertson has kindly furnished the following partic- 

 ulars of the occurrence of gold in this neighborhood (see his 

 Eeport for 1909, p. 76). 



Gold (or Mitchell) Harbour is situated on the west coast of 



*Tscherm. Min. Mitth., 1877, 1. 

 f Groth's Zeitschr., xxix, 278. 



