344 Palache and Wood — Crystallographic Study of Miller ite. 



reads _then as follows: 5, (1010), a, (1120), k, (2130), c, (0001), 

 e, (0112), r, (1011), and doubtful i, (4150), a, (5052) and i, 

 (0331). Cleavage parallel to r and e is established. 



In the Mineral Cabinet of Harvard University is a suite of 

 specimens derived from the collection of Prof. J. D. Whitney, 

 illustrating the occurrence of millerite, and its associated 

 minerals, at the old Nickel Mine at Orford, Province of Que- 

 bec. The beauty, perfection and unusual size of these crystals 

 of millerite led to their study, and examination of the litera- 

 ture revealed the fact that no detailed description of this 

 occurrence existed. Such a description is here presented, since 

 the study of this material has added largely to our knowledge 

 of the crystallography of millerite. 



The nickel deposit occurs on the east side of Brompton Lake 

 in Orford Township, Province of Quebec. It consists, as may 

 be gathered from scattered notes in the Canadian Survey 

 Reports, of a large vein chiefly composed of granular white 

 calcite which traverses serpentine. Mingled with the calcite 

 and especially abundant near the vein walls are considerable 

 masses of a bright green chrome-garnet in granular aggregates, 

 and of a light colored diopside, both granular and in long 

 stout crystals. Millerite in grains and prisms is scattered 

 irregularly through the vein matter. The deposit has long 

 been known, and it seems to have been worked for a short 

 time 'in the seventies, but was abandoned soon, the nickel con- 

 tent of the vein material, less than one per cent, having been 

 too small to pay for extracting. 



The specimens in hand consist chiefly of chrome-garnet, 

 partly in granular masses, partly in aggregates of minute indi- 

 vidual crystals held together by a cement of calcite, the 

 removal of which with acid causes the mass to crumble. In 

 the latter case, and indeed wherever the garnet is in contact 

 with the calcite, it is in sharp crystals, with the dodecahedron 

 as the dominant form. On a few crystals the dodecahedron 

 edges were truncated by planes, which on measurement proved 

 to be those of two hexoctahedrons, (358) and (459), the latter 

 new to garnet. The faces were extremely narrow and the 

 reflections poor, hence the considerable variations in the posi- 

 tion of the faces. 



Symbol. 



Miller. G,. 



(358) 

 (385) 

 (583) 

 (459) § | 

 (495) A | 

 (594) f I 



3 5 



8" 8 



5 5 



5_ 8. 



3 3 



bserved j 



32° 12' 

 21° 00' 

 3 1 ° 2 1 ' 



angles (av.). 

 P 

 35° 37' 

 60° 08' 



71° 42' 



No. of faces. 



6 

 5 

 5 



Calculated angles. 



<t> P 



30° 58' 36° 05' 



20° 33' 59° 40' 



32° 00' 72° 21' 



39° 16' 

 23° 36' 

 28° 46' 



35° 26' 

 62° 43' 

 68° 17' 



6 

 5 



38° 39' 

 23° 58' 

 29° 03' 



35° 26' 

 63° 05' 

 68° 46' 



