2 Mr. Haidinger on a new Mineral Species (Herderite). 



Cleavage distinct, parallel to the faces M, r but interrupted ; 

 also perpendicular to the axis, the latter only in detached por- 

 tions of very bright and even faces, and faint indications pa- 

 rallel to P. Fracture small conchoidal. 



Surface, M very smooth, and delicately streaked parallel 

 to its edges of combination with P, and resembling in this re- 

 spect all the faces of the pyramids, n, o, and p, situated be- 

 tween them. 



The faces r and s are very narrow, and somewhat curved. 

 Those marked t and P, have a peculiar granulated aspect, but 

 they are at the same time pretty smooth, particularly the latter. 



Lustre, vitreous, slightly inclining to resinous. Colour se- 

 veral shades of yellowish- and greenish-white ; streak white, 

 strongly translucent. 



Very brittle. Hardness = 5*0, equal to that of apatite. 

 Specific gravity =2*985. 



2. Observations. 



1. I observed and examined the characters of this species 

 in the summer of 1823, but deferred publishing the description 

 of it, with a view of collecting further observations on other 

 varieties of the same species, an expectation which was not 

 realized. The only specimen of herderite, at present known, 

 is in the Wernerian Museum at Freiberg. It was pointed 

 out to me by M. Von Weissenbach, then Keeper of the mu- 

 seum, as containing crystals, whose forms he could not exactly 

 refer to those of apatite, among the varieties of which it was 

 exhibited. The different aspect of the faces p and t, the 

 former being smooth or but faintly streaked parallel to their 

 intersections with P, while the latter are granulated, showed 

 that the forms did not belong to the rhombohedral but to the 

 prismatic system ; and I did not hesitate in pronouncing the 

 mineral to be a new species, which I requested permission to 

 examine more minutely. This permission was very liberally 

 conceded. Mr. Breithaupt, who was then present, and had 

 himself at a former period placed the specimen in the cabinet 

 of Werner, likewise concurred in acknowledging the species 

 to be a new one. 



Through the kind intercession of Mr. Reich, now keeper 

 of the museum, I was favoured, during my stay at Berlin in 

 the winter of 1825, with some fragments of the specimen for 

 analysis, by Baron Von Herder, the present Ober-Berghaupt- 

 mann, or director of every thing connected with mining pro- 

 ceedings in Saxony. It is in compliment to that nobleman, 

 that I propose the name of Herderite for the species ; and I 

 feel particularly gratified in thus expressing to one of my 



earliest 



