W. P. Blake on Crystallized Carbonate of Lanthanum. 229 
The measurements were repeated upon several crystals in dif- 
ferent parts of the field with uniform results, as here given. 
L. Il. Il. 1v. v. 
Obtuse, 93° 30/ 93° 94° g4° 93° 
Acute, 86°-86° 30/ 86° : 
On examination by polarized light, the crystals were found to 
refract doubly. 
The isolated plates or crystals appear transparent, and nearly 
colorless, but when the mineral is seen in mass it has a beautiful 
pink or rose color, and is not unlike that of peach blossoms. 
The hardness is about 2 (Mohs’s scale), or nearly that of gypsum. 
I obtained for the specific gravity at 60° I’, 2-666, which is the 
result of one determination only, and needs repeating, as minute 
BB. In tube, gives off water abundantly. With borax in oryd- 
ating flame dissolves, giving a slightly blue glass which becomes 
reddish on cooling, and when cold has a purple or amethystine 
tinge. In reducing flame nearly the same. 
With microcosmic salt; a blue glass, while hot amethystine, 
and red when cold; the bead becomes opaque when but slightly 
heated, and retains a pink color. With carbonate of soda, a 
green reaction similar to that given by manganese. 
The crystals dissolve rapidly in dilute chlorohydric acid, with 
brisk effervescence; ammonia precipitates from this solution a 
bulky precipitate of a delicate pink color which is insoluble in an 
excess of the precipitant ; the filtrate leaves no residue on being 
€vaporated to dryness. 
The following are the chemical characters of the mineral as 
given by Prof. J. Lawrence Smith, who has kindly examined it 
for me. 
“he mineral gives all the reactions for lanthanum and didy- 
i 
sulphate deposits on boiling small prismatic crystals, which, redis- 
solved on the cooling of the solution, afford unmistakable evidence 
of the presence of sulphate of lanthanum or its like. } 
eral when heated to redness loses all its water, anda large portion 
of carbonic acid, but it requires a long continued heat to expel the 
last traces; the residue is of a light brown color; if this be treated 
With nitric acid re-ignited and then thrown into water containing 
