34 
SALOON. 
Nat. Hist. 
Case 27. Strontian salts; carbonate of stron- 
tian, also called strontianite, in prismatic and 
acicular crystals, which latter have sometimes 
been mistaken for arragonite.—Among the sul¬ 
phates of strontian (celestine of Werner) the more 
remarkable specimens are, the splendid groups 
of limpid prismatic crystals from La Catoiica in 
Sicily ; the acicular variety in the hollows of 
compact sulphate of strontian, from Montmartre; 
the same in fissures of flint; the radiated and 
fibrous celestine, &c. 
The remainder of this case is occupied by some 
other saline stony substances, viz. carbonate of 
magnesia, called also pure magnesia, and mag¬ 
nesite. Borate of magnesia, or boracite^ in sepa¬ 
rate crystals, and the same imbedded in gypsum ; 
-—hy dr argillite or voavellite , which may be consi¬ 
dered as a phosphate of alumina; azurite and 
blue spar (Werner’s lazulitand blauspath), which 
appear to be phosphates of alumina, magnesia, and 
silica : \—aluminite , a subsulphate of alumina, from 
Sussex, and from Halle in the territory of Mag¬ 
deburg, which was formerly mistaken by some 
for pure alumina, by others for a hydrate of alu¬ 
mina with mechanically admixed sulphate of 
lime: it must not be confounded with alum-stone 
(alunite of French mineralogists), which, accord¬ 
ing to Cordier, is a hydrate of alumina with an¬ 
hydrous sulphates of alumina and potassa. Fluate 
of soda and alumina, or cryolite (found only in 
West Greenland), pure and intermixed with 
brown 
