PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 63 
The analysis on 25 grains yielded— 
Silica, 5 : , . 29°894 
Alumina, . ‘ ; SAO Si 
Chromium Sesquioxide, . 5:*967 
Ferrous Oxide, . : A eQbo 
Nickel Oxide, . ; . trace 
Lime, , : : oo Bb 
Magnesia, ‘ : ae oo 
Potash, *~. , ‘ oe eda 
Soda, ; é : ; “974 
Water, . : ; . for 206 
Carbonic Acid,. ‘3 igeee: . 
99-616 
4, Five and twenty years after the first discovery of this very rare mineral 
in Unst, it was again obtained by Mr DupceEon and myself among the vein- 
stones of a new chromite quarry which lay to the north-west of the House of 
Buness, some two miles from the original locality. It was here occasionally in 
fairly well-formed crystals, which are elongated rhombohedra. 
The cleavage folize of these crystals are optically uniaxial, or with a very 
slight axial divergence. Their colour is a bright purple. They are over a 
quarter of an inch in length and breadth. 
1°38 grammes yielded— 
Silica, : : ‘401 
From Alumina, . ‘019 
VAD, = a2, 307 
Alumina, , 7°497 
Chromium Sesquioxide, . 7° 888 
Ferrous Oxide, 2° 076 
Lime, 3° 833 
Magnesia, 32°153 
Water, 14: 246 
99-90 
Insoluble silica, 5: 233. Was apparently pure. 
At both of the above localities of Kammererite it was associated with a 
pulverulent substance of a light-yellow colour. Analysis showed this sub- 
stance to be new. I have elsewhere described it under the name of Hibbertite. 
5. Pseudophite.—This allomorph, which I now introduce as new to Britain, 
was obtained by Professor Nico and myself from the east side of Beauty Hill, 
in Aberdeenshire. 
VOL, XXIX: BART I. R 
