PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 243 
From Eajiltration Veins in Grey Granite. 
4, A large vein, almost solely quartz, occurs in the granite quarry a mile 
west of Dyce, in Aberdeen. Rarely in the massive quartz there are imbedded 
crystals of silvery muscovite associated with finely formed crystals of nearly an 
inch in size of oligoclase. These crystals are, however, perfectly opaque, white 
in colour, and lustreless,—they are not striated. There is no orthoclase in the 
vein. 
The cleavage angle is 86° 15’; the specimens were too porous to determine 
the specific gravity upon. 
25 grains yielded — 

Silica, . : 5 dl) POS) 
From Alumina, . 0 ayalis! 
16h, = 64-846 - 
Alumina, . : : NB EHD 
Magnesia, . - 202 
Lime, . ; : : : - 964 
Potash, ; Miah Pre 
Soda, . : ; : eg te 245) 
Water, ; ; ; : - 008 
LO eg 

Insoluble silica, 18°23 per cent.; possible impurity, quartz. This being 
an almost non-calcareous oligoclase. 
. 
. 
5. From veins in Sclattey Quarry, near Buxburn, Aberdeenshire. The 
oligoclase here is associated with delicately flesh-coloured orthoclase, and 
Haughtonite. It is white in colour, and obscurely and very minutely striated. 
1°264 grammes yielded— 
Silica, . ‘ e225 
From Alumina, 03 
(o20 = 59 aa 
Alumina, . ; : Bi 7 ant 1155 
Ferric Oxide, : ; aoe fee Sil: 
Magnesia, . : ; EOS 
Lime, . : s eo Gan 
Potash, : 5 ; reg Serie} 
Soda, 23 
Water, 1-881 
100 746 
Insoluble silica, 4°12 per cent.; possible impurity, orthoclase. 
