12 NOTES ON THE OCCURRENCE Ol' A (iREEN MIXBRAL,, ETC. 



rbceutly received at the Queensland Museum from Mr. Aird, 

 of Sea Hill, who obtained them from the Keppel Rocks at 

 jny request. 



As far as I am aware no description of it has been hitherto 

 published in Australia, but that it has attracted attention 

 may be concluded from the fact that for some time past speci- 

 mens have been received by nie for determination from the 

 workmen engaged in the excavation, and from foot pa^seng^rs 

 passing the spot ; their curiosity in each case had, doubtless, 

 been attracted by the beautiful colour which the substance 

 .exhibits. 



The following is a description of its different physical and 

 chemical properties, kc. : — 



The mineral generally occurs tilling and lining the joints 

 ami small cavities in the enclosing rock ; in several instances it 

 occurs in isolated patches in these joints, the intervening space 

 being occupied by an earthy ferruginous substance, and, except 

 in the latter case, it adheres firmly to the matrix. It is met 

 with in ail amorphous compact form without any trace of 

 cleavage : also less frequently as mammilated, botryoidal, 

 stalactitic, and incrusting masses. It is brittle and has a 

 smooth, sub-conchoidal fracture with a tendency to break into 

 thin flakes (one isolated specimen possessed a somewhat 

 granular fracture when broken) ; lustre dull, but sometimes 

 waxy on the surface of the incrusting mass ; it varies in colour 

 from apple-green to dark sea-gi'een, and several of the speci- 

 mens obtained were spotted and streaked with white ; sub- 

 translucent on thin edges ; the hardness varies from 4 to 5 ; the 

 specific gravity is 2-6. It appears to bleach on exposure and 

 decomposes, forming a white pulverous substance. 



, Small fragments heated in the closed tube yield water and 

 a^^|ume ^ pale lavender colour ; it is slightly attacked by acjds ; 

 j.t gives no colouratj.on to the flame when moistened wiih 

 sulphuric acid ; when heated on charcoal it decrepitates ; it .is 

 i|c^fii$jibl{9, .and wi^th iiu^rososnjic salt it gives a faint reaction for 



