1 130 The. new Mineral Newboldite. [Nov. 



Our entire specimens are unfortunately very small, and thus I have 

 been excessively cramped in my researches, for as will be seen, it is 

 scarcely possible to obtain pure fragments even of a very small size. 



I should describe it, as to external appearance and physical proper- 

 ties, as follows : — It is, where purest, and not weathered, of a clear 

 apple-green, with considerable lustre on some of the facets of the 

 numerous imperfect crystals of which it is formed, giving it the pearly 

 glimmer of a green mica or of some of the green carbonates of Iron in 

 a o-ood light. Where weathered it is of a bluish grey-green, and the 

 glance is more minutely silvery or micaceous, or at times steel-like. 



Minute fragments of the pure mineral are semi-translucent at the 

 edges, like those of fine apple-green serpentine. 



When powdered its colour is of a very light greenish buff or fawn 

 colour, becoming a little darker, or greenish, when exposed to a very 

 gentle heat to drive off the little water it contains. When pulverising, 

 if smartly rubbed or struck it emits a very perceptible odour of sul- 

 phuretted hydrogen. 



Its hardness is 3-4 scratching Calc-spar, but not Fluor. 



The streak is of a dirty fawn coloured white, but always with a minute 

 silvery line at the centre where the knife has cut. 



It has a slight earthy smell when breathed upon. It is brittle and 

 easily pulverised. 



The fracture is hackly, and highly glistening ; the fragments are at 

 times laminar and angular, but in truth they are so small and the nests 

 and veins of the mineral so diminutive that it is not fair to judge of 

 these characters. It seems to cleave readily in certain directions, but 

 what these are cannot be judged of yet ; the larger fragments incline to 

 cubical on rhomboidal prismatic forms. 



It does not soil, or mark, or adhere to the tongue on the fresh 

 fracture. 



The crystals are too small, confused and imperfect to judge well of 

 their form, which however appears to approach to that of rhomboidal 

 prisms. 



The mineral seems much subject to decay by the oxidation of the 

 iron, which is distinctly seen in some parts, leaving in the quartz what 

 are called in Cornwall vuggy cavities (i. e. rough, jagged, and full of 

 irregular ridges) coated with the peroxide of iron. 



