8 NEW YORK STATE MUSEUM 



Second type. The scalenohedron A (15.4. 19.3) which is common 

 in crystals from this locality is developed in long, slender forms, 

 the brilliant faces of which give excellent reflections and are sus- 

 ceptible of exact measurements. The rhombohedron e (01 12) 

 terminates this type [fig. 7]. Twins occur according to two laws, 

 parallel to c (0001) and parallel to e (01 12). The pyrite inclusions 

 observed in connection with crystals of this type take the form of 

 phantoms outlining the faces of a steep scalenohedron, possibly A 

 (15.4. 19.3). The largest crystals of this type were 25 mm in length. 



Third type. As in the preceding type the scalenohedron A 

 (15.4. 19.3) and the rhombohedron e (01 12) form the distinguish- 

 ing habit of this type, but developed in rather more equal propor- 

 tions, giving rise to crystals of rather blunter aspect. The basal 

 scalenohedral edges are beveled by the prism e (11 20) and those 

 between the scaleonohedron and rhombohedron by the small tri- 

 angular faces of the rhombohedron M (0441), this latter being only 

 occasionally present. The basal plane c (0001) is also occasionally 

 present in this type [fig. 8]. Twins are of frequent occurrence 

 parallel to c (0001). The largest crystal noted measured 8 centi- 

 meters in length. 



Fourth type. Crystals of this type, which were noted on but one 

 specimen, are of prismatic habit showing a (11 20) terminated by 

 the rhombohedron e (01 12) and modified by the positive scaleno- 

 hedron A (15. 4. 19. 3) and the negative scalenohedron n (3. 16. 19. 2) 

 [fig. 9]. Crystals are small but with bright faces giving fair re- 

 flections. 



Fifth type. Crystals of the fifth type though by no means com- 

 mon were noted in a number of instances. They are characterized 

 by the equal development of the rhombohedrons e (oii2)and rj 

 (0441), the modifying form being the prevailing scalenohedron A 

 (15.4. 1 9.3). The rhombohedrons of this type are notably striated 

 parallel to their intersection edges [fig. 10]. 



Sixth type. Crystals referable to this type are quite common, 

 being noted in as many as eight specimens. They are of rhombo- 

 hedral habit, the preponderance of the rhombohedron T (0.12.12.1) 

 (new) giving to them an aspect almost prismatic. The rhombo- 

 hedron I (0445) which with e (01 12) terminates the type is of vari- 

 able development from a face equal to e (01 12) in habit to a mere 

 line [fig. 11]. Vicinal planes are frequent in crystals of this type 

 and are often present to such an extent as to modify the basal 

 edges to curved lines and give to the crystal the aspect shown in 

 figure 12. 



