114 Mr. William Phillips on the OxydofUraniuml 



it seems probable that both its colour and hardness may be ascnbe4 

 to the dissemination of that substance throughout the mass, which 

 leaves a black streak on paper. Some specimens also abounded 

 with pyrites both arsenical and martial, and some of them have 

 decomposed since they came into my possession. The veins of 

 Tol Cam mine afforded little or no copper ; the uranium was 

 found in one of them at about 30 fathoms from the surface. 



The colours of the crystals both from Tol Cam and Tin Croft 



mines are nearly the same. They vary from almost opake 



white to yellowish, and pass into the most brilliant yellow; 



isorae being transparent, others opake. Of some tabular crystals, 



the center is transparent and nearly colourless, and the edges are 



yellow. On other specimens the crystals are transparent and of a 



greenish hue, whence they pass through almost every shade, into 



deep grass green ; while in others, the center of the crystal is 



yellow and the edges only are green. Again, from a brownish 



tinge they pass into a rich brown, but as the surfaces of these 



crystals glisten, the colour seems to be original ; while on many 



specimens the crystals, which are of a light green colour, are 



hollow at their centers and of an ochreous brown, a circumstance 



arising doubtless from decomposition, and which in other specie 



mens has proceeded so far as that the forms of the crystals can no 



longer be defined. * 



The crystals on some specimens from Tin Croft mine are 



accompanied by spiculse of blue carbonated copper j in others, by 



green carbonated, and red and black oxides of copper, and on one 



specimen, they are deposited on minute spiculae of oxide of iron.' 



I have some specimens of the red oxyd of copper from the mine 



called Hue! Jewel, on which there are very numerous and minute 



tabular crystals of the oxyd of uranium of a light green colour. 



