UNUSUAL TOURMALINE-ALBITE ROCK FROM ENOGGERA. dL 
than the tourmaline, and has occupied sinuous cavities or 
replaced veins in the tourmaline rock. The size of the felspar 
erystals is variable, but usually one individual occupies the 
whole width of the vein. 
In addition to the veins, however, smaller crystals of 
felspar occur in the heart of the matted tourmaline. 
In other cases, particularly in the smaller veins and along 
portions of the margins of the larger, the felspar is present as 
groups of small crystals. 
(IV) CHEMICAL. 
In order to further investigate the nature of the minerals 
of the tourmaline-albite rock, quantitative chemical analyses 
were decided on. Part of one of the felspar bands was carefully 
removed, piece by piece, from the rock. This felspathic 
material was then ground very finely, and all traces of tour- 
maline removed by a powerful electro-magnet. In this way 
a small amount of the felspathic material was obtained in a 
fairly pure state. This was analysed by Mr. G. R. Patten in 
the laboratory of the Queensland Agricultural Chemist, with 
the result shown in the first column of Table 1. 
In order to provide the analyst with a larger quantity of 
material for the more difficult analysis of the tourmaline, a 
sample of the massive tourmaline from the edge of the granite 
was sent in preference to that which had been separated from 
the tourmaline-albite rock. The mineral submitted appears 
to be identical with that of the tourmaline-albite rock in colour, 
size and habit of crystals, and general appearance. The sample 
forwarded was seen to contain, however, as an impurity a 
considerable quantity of small red crystals of hematite. 
Consequently particular care was exercised by Mr. Patten in 
the determination of ferric and ferrous iron. 
The resulting analysis showed 7-43 per cent. of Fe,O, out 
of a total of 99-95. This was assumed to be present in the 
form of hematite, and was consequently subtracted from the 
total, which was then recalculated to 100 per cent., with 
the result set out in the second column of Table 1. 
As a matter of interest, two further analyses appear in 
Table 1. These are analyses of the Brisbane Schist and of 
the Enoggera Granite (Pink Phase) respectively. Neither of 
