35 
or witherite, may be particularized the beautiful 
groups of double six-sided pyramids, and those 
of six sided prismatic crystals. 
(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 Catolica 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, See. 
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 ; 
—-by dr argillite or wavellite , which may be consi¬ 
dered as a phosphate of alumina; azurite and 
blue spar (Werner’s lazulit and 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- 
d 2 hydrous 
saloon. 
Nat. Hist. 
