242 Mr Haidinger on Sternhergite, 



brown, or blackish-brown, and it loses from 20 to 50 per cent, 

 of its weight. Before the blowpipe it instantly blackens, and 

 becomes susceptible of magnetic influence. When immersed 

 in muriatic acid, it dissolves slowly, with effervescence, and 

 leaves a residue composed of a mixture of argillaceous and bi- 

 tuminous matter. This solution, which is of a greenish-yellow 

 colour, on receiving the addition of nitric acid, becomes for a 

 few seconds of an intense olive-brown, and almost immediately 

 after loses this appearance, turning yellow, and giving off at 

 the same time copious nitrous fumes. When smelted in the 

 blast furnace, the ore yields, on an average, about 30 per cent, 

 of cast iron. 



(To be continued*) 



Art. V. — On Sternhergite, a New Mineral Species. By 

 William Haidinger, Esq. F. R. S. E. &c. Communi- 

 cated by the Author.* 



I. Description. 



Fundamental form. A. scalene four-sided pyramid. P=128^ 

 49^, 84° 28', 11 8<^ 0^. Plate III. Fig. 1. 



a: b : c = l : V 1.422: VO.484. 

 Simple forms. P— oofaj,- V (f) ; V -\. 1 (g) = 122=* 

 1 7', 68° 22', 146° S4' ; (Pr) ^ (d) = 92° 28', 107° 17', 131° IT, 

 |>r J- 1 (b) = 6P 35', f Pr + 3 r^; = 13° 36', Pr -}-co (i) ; 



Various combinations among these forms have been observ- 

 ed, one of them is represented, Fig. 2. They have all more 

 or less the aspect of rhombic plates, with angles of 119° 30', 

 and 60° 30', which is the base of the fundamental pyramid ; 

 often the acute angle is truncated. 



Cleavage highly perfect, and easily obtained parallel to the 

 face a. No trace of cleavage in. other direction of the lamel- 

 lae, which may be torn asunder like thin sheet-lead. 



Surface of a delicately streaked parallel to the edges of com- 

 bination with h, that is parallel to the long diagonal of the 

 rhombic plates. Lustre more considerable upon these than 



• Abstract of a paper read before the Royal Society of Edinburgh on the 

 4th of December 1826. 



