DESCRIPTION AND ANALYSIS OF A NEW 

 SPECIES OF MINERAL, PETTERDITE, 

 A NEW OXYCHLORIDE OF LEAD. 



By W. H. Twelvetrees. 



This apparently absolutely new chemical combination 

 occurs in attached crystal groups in a quartz gano'ue 

 containing disseminated pyrites, in the form of somewhat 

 thin hexagonal plates, which are usually minute in size 

 (about 5 millemetres in 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. 

 S&eak : — W^hite. 

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



shining on the edges of the crystals. 

 Hardness : — 15 to 2. 

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



Government Analyst. 

 Before blowpipe: — On coal OF. forms white to 



yellow^ mass. RF. a bead of 



metalhc lead is easily produced 



without fluxes. 

 Heated in forceps, strongly decrepitates. 

 Flame: — With OCu distinctly azure blue. In 



powder with H^ SO^ dull greenish 



blue. 

 In cold HJSO ^ dissolves quietly and very slowly ; 



in hot acid dissolves slowly, giving 



with AqNOo a thick, curdy 



precipitate. 

 The powder heated before blowpipe gives slight 



odour of AS2O5. 



