Intelligence and Miscellaneous Articles. 



4.61 



STERNBERGITE, — A NEW MINERAL SPECIES. 

 I. Desckiption. 

 Fundamental form, A scalene four-sided pyramid. P=128° 49', 

 84° 28', 118° 0'. Fig. 1. 



a: b: c=l : Vl-422 : ^0-484. 

 Simple forms. P- oo(a) ; P (/) ,• P + 1 (g) = 122° 17', 68° 22', 

 146° 34'; (Pr)5(ti)=92°28',107°17',13P17',Pr+ 1(6)= 61° 35' 



i Pr + 3 (c) = 13° 36', Pr +qo (i) ,- -t Pr-3 (ft) = 153° 2'. 



Various combinations among these forms have been observed, one 

 of them is represented, Fig. 2. They have all more or less the aspect 

 of rhombic plates, with angles of 1 19° 30', and 60° 30', which is the 

 base of the fundamental pyramid ; often the acute angle is truncated. 



Fig. 2. 



Cleavage highly perfect, and easily obtained parallel to the face a. 

 No trace of cleavage in other direction of the lamellae, which may be 

 torn asunder like thin sheet-lead. 



Surface of a delicately streaked parallel to the edges of combination 

 with h, that is parallel to the long diagonal of the rhombic plates. 

 Lustre more considerable upon these than upon the remaining faces, 

 which are deeply streaked parallel to their intersections with a. 



Lustre metallic. Colour dark pinchbeck-brown, rather darker than 

 the colour of magnetic pyrites. Streak black. Tarnish, often violet- 

 blue on all the faces except a. 



Very sectile. Thin laminae perfectly flexible. Hardness = l"0...1-5, 

 little superior to talc. Specific gravity = 4215. 



Compound varieties. Twin-crystals, joined parallel to a face of 

 P + 00 . Generally several crystals are joined in an irregular man- 

 ner, and implanted together, being fixed to their support with one of 

 their sides, so as to produce rose-like aggregations and globules, 

 with a drusy surface. Massive varieties usually present the a.spect of 

 a coarse-grained mica. 



II. Observations. 



1. The two specimens from which the preceding description is 

 drawn up I first saw when in Prague in March 1826. They were 

 pointed out to me as something not agreeing in several respects with 

 the known species, by Professor Zippe, one of them in the collection 

 of the National Museum, the other in tiie collection of Gubernialratb 

 Neumann ; the latter specimen was designated on the ticket as a 



pinchbeck- 



