MIX ERA LOOK' A I. NOTES AN'nKUSON. 



Crystal vii. (PL i., f'J?. <'), also from Heffernan's Mine, .s similar to 

 tliepreeedii.g but the markings oi, the base are more prononiu-e.l ami he 

 pyramid facL are almost obliterated. The narrow ,. faces b.-uiulmg the 

 elevations on the base are seen in the goniometer telescope as a series ..t 

 bright, pai-allel lines. 



CiTstal viii. (PI. i., figs. 7, 8, PI. ii., fig. 7) is the pi-operty of Mr 

 George Smith, Inspector of Mines, who kindly lent it for descrVion. 

 is believed to be the finest crystal obtained from Heffernan s Mine. It 

 measures 45 X 4-8 X 3-5 cm. and is bluish green in colour with numerous 

 internal fiaws. In the line drawings the faces ^^e shown ^ithou 

 markings, the photograph (PI. ii., fig. 7) gives a good idea of the basa 

 p laneafi reall/is. To obtain this photograph the crystal was backened 

 underneath and on the sides and the base coloured a slaty tint with a 

 fixture of lamp black and Chinese white; the result surpased 

 anticipation. The faces of the prisms are striated vertically and the 

 T.yi-anlids are much corroded. The base is traversed by a series ot 

 J'luUies" which zigzag across the face ; the general direction of these 

 gullies seems quite arbitrary in cases, but closer inspection shows that 

 they are made up of short lengths which run parallel to the intersections 

 7p- tiey are flaa.ked by planes of ,. In addition to the gullies here are 

 L^^n'umbJr of hexagonal 'elevations, especially in f «^ -"^^^ J^^P^s 

 portion of the base. These elevations are bounded by aces of the base 

 ind the pyramids p and, less frequently, v and .. m addition The ma 

 basal surface is covered with thin plates, some regularly hexagonal in 

 outline, others irregular in shape, but all with straight boundaries 

 parallel to the edge r/p, and having edges formed by narrow faces oty. 

 These plates are perhaps the result of oscillatory combination be ween 

 and ^. If one imagines the gullies filled in, the base of the crystal would 

 then resemble that of crystal vii. 



Crystal ix. (PI. ii., fig. 6), which comes from Heffernan's, present^ a 

 striking and puzzling appearance. The photograph repi-esent^Jie 

 termination of a crystal measuring 4-5 cm. in greatest diameter. Round 

 the edges of the base we find a succession of terraces which would seen 

 to indicate that the basal surface has been progressively stripped off, and 

 the whole base is intersected by a series of broad " valleys separating 

 numerous hillocks. It is difficult to avoid using the anguage o 

 physiography in describing this crystal for it strongly resembles an island 

 of horizontally bedded rocks which is being terraced by the sea, and the 

 surface of which has been carved into a network of gorges and Hat 

 bottomed valleys, trending roughly parallel to the prism ^^^^^ J'l"';^ 

 form the coast line, and separated by numerous residuals and mesas and 

 occasional sharp pinnacles. The mesas are margined by faces o 

 ,. (1011) and more rarely . (2021), which are sometimes pitted am 

 paHly eaten into by flutings which run parallel to the vertical axis and 

 deeply score the bounding prism faces of the crystal. 



Apart from the large scale features the basal surfaces are in places 

 covered with small pits, some distinctly hexag.mai, others apparently 

 circular On the faces of the unit pyramid bounding residuals a few etch 



