DESCRIPTION AND ANALYSIS OF A NEW 

 SPECIES OF MINERAL, PETTERDITE, 

 A NEW OXYCHLORTDE OF LEAD. 



By W. H. Twelvetrees. 



— ^♦- 



- This apparently absolutely new chemical combination 

 occurs in attached crystal groups in a quartz gangue 

 containing disseminated pyrites, in the form of somewhat 

 thin hexagonal plates, which are usually minute in size 

 (about 5 millemetres iu diameter), but occasionally reach 

 9 mm. dia., and, still more rarely, a larger size. 



Macles are not rare, irregularly attached and implanted 

 on each other, and on the matrix. 



Fracture: — Rather irregular, brittle and dull. 

 Colour : — White, passing to pale grey on the 



surface. 

 Streak : — White. 

 Lustre: — Dull, inclined to rough, waxy, opaque,, 



shining on the edges of the crystals. 

 Hardness : — 1'5 to 2. 

 6rrau% ; — 7-16, determined by Mr. W. F, Ward, 



Government Analyst. 

 Before blowpipe: — On coal OF. forms white to 



yellow mass. RF. a bead of 



metallic lead is easily produced 



without fluxes. 

 Heated in forceps, strongly decrepitates. 

 Flame: — With OCu distinctly azure blue. In 



powder with H2 SO^ dull greenish 



blue. 

 In cold HNO^ dissolves quietly and very slowly ; 



in hot acid dissolves slowly, giving 



with AqNO^ a thick, curdy 



precipitate. 

 The powdei' heated before blowpipe gives slight 



odour of AsgOg. 



