104 
LONG 
GALLERY. 
Nat. Hist. 
specimens selected to illustrate the crystalline forms of 
the diamond are:—the primitive regular octahedron; 
the same with solid angles truncated; with edges trun¬ 
cated, forming the passage into the rhombic dodecahe¬ 
dron; varieties of the latter, giving rise to the six-sided 
prismatic and the tetrahedral forms ; cubes with trun¬ 
cated and bevilled edges ; various hemitropic crystals or 
macles of diamonds, an octahedral diamond in its 
matrix, &c. With these are placed specimens of the 
alluvial rocks in which this precious substance occurs in 
the East Indies and in Brazil. Among the specimens 
of anthracite or kohlenblende (to which may be referred 
the Kilkenny coal) is a specimen from Kongsberg, in 
Norway, with native silver;— graphite, (commonly called 
black-lead, massive, disseminated in porcelain earth, 
&c.)—Of Seleniurets , only those of copper and silver 
(Eukairite), of lead and copper, and the selenium sul¬ 
phur, are at present in the collection. 
Case 5. The suite of specimens of sulphur (crys¬ 
tallized, massive, and stalactic, with selenite, sulphate of 
strontian, &c.; and the same found sublimed near the 
craters of volcanoes, &c.) is succeeded by the Sul- 
phurets , which occupy half of this and seven of the 
succeeding table cases. They begin with sulphuret of 
manganese or manganese-blende, from Nagyag in Tran¬ 
sylvania, and from Peru.—Among the numerous varieties 
of sulphuret of zinc , or sine-blende, may be particu¬ 
larized those relative to colour, viz. the yellow, the 
brown, and the black blende of Werner; the first of 
which is generally most pure, while the others contain a 
portion of iron; the fibrous blende of Przbram in Bo¬ 
hemia, in which cadmium was discovered by Stromeyer; 
the variety called testaceous or schaalen-blende, the 
most characteristic specimens of which are from Ge- 
roldseck in the Brisgau, contains, besides iron, a por¬ 
tion of lead. 
Case 6.— Sulphurets of iron , or iron pyrites: — com¬ 
mon pyrites , smooth and striated, variously crystallized ; 
—radiated pyrites, a substance very subject to decom¬ 
position, 
