: ORTIIORIIOMBIC SYSTKM 



119 



The ri^ht sphenoid, with four similar scalene triangular faces, 



iK. L';;:; ;m<l Fig. - ; H, i- tin- complementary left form. 







Fio. 232. Type 6, Digonal 

 Holoaxial. 



FIG. 233. The Right 

 Sphenoid. 



Other forms are similar in appearance to those of type 8. 



Forms possible to combine in this type will therefore be: 



Right and left sphenoids, K(hkl) , K(hkl) . 



Orthorhombic prisms, (hko). Macropinacoids, (100). 



Macrodomes, (hok). Brachypinacoids, (010). 



Brachydomes, (ohk). Basal pinacoid, (001). 



Examples. Sulphur, S, Fig. 235, represents a combination of 

 the right and left sphenoids and the base on sulphur. 



Epsomite, MgSO 4 .7H 2 0, Fig. 236, is a 

 combination of the prism and right sphenoid 

 as found on crystals of this mineral. 



Fio. 234. The 

 Left Sphenoid. 



FIQ. 235. Sulphur. 



FIQ. 236. Epsomite: 

 Combination of (110) 

 and (111). 



