312 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
Iron—Alumina Garnet. 
(Fe’)*Si? + Al?2Si*. 
Common Garnet. 
From Gneiss. 
4. Occurs imbedded abundantly in micaceous gneiss about two miles north- 
west of Burra Voe, Yell, Shetland, near the junction of said gneiss with an 
epidotic rock (?the epidotic syenite of Hissert). At this spot the epidotic 
rock overlies micaceous gneiss, and is itself overlaid by the hornblendic. The 
dip is to the west of north, at an angle of about 15°. 
The garnets here are fine in colour, being of a lively pinkish red ; they are 
much flawed. Specific gravity, 3°997. 
1°303 grammes yielded— 
Silica, : : : * 468 
From Alumina, . ; °018 
‘486 = 387:298 

Alumina, . ; . »  2i 095 
Ferric Oxide, . : , Toy 
Ferrous Oxide, . ’ 5) 2a ODE 
Manganous Oxide, ; 2°141 
Lime, ‘ : A : 4-426 
Magnesia, . 3°53 
99 - 983 
Insoluble silica, 2:056 per cent.; possible impurity, quartz. 
From Mica Slate. 
5. From Ben Bhrackie and Killiecrankie, in Perthshire. On the south-west 
slopes of Ben Bhrackie the garnets are of small size; they occur along with 
lanceolate crystals of hornblende, imbedded in a granular paste of felspar and 
quartz of a cream colour; forming a rock which, when slit and polished, is 
possessed of considerable beauty. 
At Killiecrankie the garnets are of the size of bullets, and are imbedded im 
a dense fine-grained laminated paste of mica. Their colour is a brownish red; 
their structure is fine granular, with minute granules of quartz very frequently 
intermixed. Specific gravity, 3: 688. 


