OHDER II. PYRAMIDAL LEAD-BARYTE. 143 



2. Pr. P. (Pr + oo) 3 . Pr + oo. Leadhills, 



Scotland. 



3. Pr. P. (Pr+oo) 3 . (Pr + x) 4 . Pr+oo. 



Leadhills, 



4. Pr. Pr. P. (Pr + oo) 3 . Pr+oo. Sim. 

 Fig. 21. Mellanoweth, Cornwall. 



5. (Pr 2) 3 . Pr. Pr. P. (Pr + oo) 3 . 



Anglesea. 



6. P 1. Pr. (Pr I) 3 . Pr. P. (Pr+oo) 5 . 



Pr + oo. Siegen, Prussia. 



Cleavage Pr and Pr + QD, imperfect and interrupt- 

 ed, the latter rather more distinct. Traces of 

 P oo. Fracture conchoidal. Surface, P 1 

 and (Pr 2) 5 uneven, curved and almost al- 

 ways rough ; the faces of Pr + GO and the verti- 

 cal prisms are often striated parallel to the axis, 

 Pr + oo in a horizontal direction, and (Pr I) 3 

 parallel to the edges of combination with P. 

 In general the faces are smooth, and often of 

 high degrees of lustre. 



Lustre adamantine, inclining to vitreous or resin- 

 ous. Colour yellowish-, greyish-, or greenish- 

 white, also yellowish-, smoke-, and ash-grey. 

 Sometimes faintly tinged green or blue. Streak 

 white. Transparent ... translucent. 

 Brittle. Hardness = 2-5 ... 3.0. Sp. Gr. = 6-298 

 of white semi-transparent crystals from Leadhills. 

 Compound Varieties. Massive : composition la- 

 mellar, also granular of various sizes of individu- 



