73 



TAB. CCCXLII. 



PLUMBUM carbonatum. 

 Carbonate of Lead. 



Div. 1. Crystallized 5 in hexaedral lamince. 



Carbonate of Lead of this form and colour has for 

 many years been considered as a Molybdate. Its readily 

 effervescing in dilute Nitric Acid will, however, betray it. 

 The modifications of the present specimen are remarkably 

 striking, and are evidently to be traced from, or to, the 

 plated forms of tabs. 89, 90, and 91. The Crystals have a 

 light glare, and somewhat pearly lustre, and are in colour 

 from nearly white to greenish yellow; scattered in irregular 

 fissile hexangular plates, or more compact : — see the middle 

 figure, which contains plates nearly like the lower left hand 

 outline, or piled up as that on the right hand. 



These specimens are very rare, and occur only now and 

 then in the Wanlock-head mines near Glasgow. I have 

 one from Mr. Day's collection, some years old ; and some 

 by means of other friends. I do not know that they are 

 found elsewhere, or are at all described as green, or ap- 

 proaching thereto. They are said to be snow-white, grayish 

 and yellowish-white, cream-yellow, and clove-brown. 



