92 Anthracite Coal of Rhode-Island. 
the richness and beauty of these adventitious colours. The 
most brilliant are blue, green, yellow and red, which, heing 
disposed in clouds and bands, upon a ground of brillian 
black, form a combination rarely surpassed in beauty.* 
The lustre is resplendent and vitreous. There is a very 
high natural polish, which, united with the black colour, im- 
s to this substance, singular beauty. Its aspect is very 
much like that of obsidian, and from its appearance, we should 
sooner it for a vitreous than a carbonaceous compound.* 
Hardness. This anthracite a but 
it wears files and saws, thus evin its integrant parti- 
cles are hard. The powder is ache aE soils the hands like 
charcoal.. When the fragments, such as are used for burn- 
nt are freed by washing and wiping, from the fine dust of 
coal, which adheres to them, they then cease to soil the 
_. and will not tarnish even white paper, or clean linen, 
although impressed upon the surface with considerable force. 
By strong ignition, this anthracite becomes hard enough to 
scratch glass. 
mean specific gravity is 1.55. The Schuylkill variety 
apipckrs to be a little less; about 1.52; and it is very possi- 
ble that an examination of a greater variety of pieces would 
present also more variety in the results. 
The structure ts slaty—apparently, in the direction of the 
strata, (for I have not seen it in a In many specimens, 
is striking, and in all that I 
that is so le i 
‘The slaty structure may probably be regarded as the result 
of the general geological laws, that influenced ‘the deposition 
of the coal, considered as a member of the series of rocks, of 
peculiar formation, 
‘Thave selected specimen after specimen from the fragments that were 
aoe to be thrown into the furnace, Seu the shelves were inc 
the least beautiful wer were at length committed to the fire. 
; ‘specimens, even when not 
te to an_ inconvenient . Few ~ the a 
cimens in cabinets are équally beautiful, and Tam mut informed of the exist- 
ence of any anthracite, Which admits, in this i 
wedi Bier tis in 8 Semmes of the Rhode- Island coal, bat it is much less 
