This substance, which forms veins in tte serpe itin 
Hoboken, is in all probability one of the most deceptn 
erals ever discovered, since it appears in every respé ch as a 
well characterized variety of amianthus for which it had-al- 
ways been mistaken. It possesses the usual silky lustre 
and flexible fibrous texture, and is commonly ofa pale blue 
colour. It cannot indeed like the genuine amianthus be re- 
duced to a flocculent mass, so as to be twisted and spun, 
and the fibres when presented to the flame of a lamp, in- 
stead of running up into a globule, like that of Massachu- 
setts, remain infusible, become friable, opaque and rigid, 
and at the same time assume alight browntinge from the oxi- 
dation of the iron contained in them. But the most singular 
character which this deceiving mineral presents, is its total 
solubility in acids, without effervesence, except in such 
fragments as have been exposed to the weather, or which 
are slightly contaminated by carbonate of lime. Its spe- 
cific gravity I found to be 2,44. 
By exposure to a considerable heat, in the experiment 
which I made it lost 30 per cent. and in sulphuric acid was 
all converted into a well characterised epsom salt, excepting 
about a grain of lime and a precipitate of iron, equivalent to 
about 5 per cent. of the protoxide. 
This mineral when rubbed with a piece of iron as well as 
the lamellated magnesite phosphoresces with a yellowish 
light. 
Marmolite. 
This mineral, which has hitherto been considered in this 
country as a variety of talc, forms also narrow veins in the 
serpentine of Hoboken, and in that of the Bare Hills near 
Baltimore ; in the former locality it sometimes occurs in 
contact with the lamellar oe of magnesia and in the 
magnesian marble. ne 
Its texture is foliated with the lamina thin, and often 
parallel asin diallage. Sometimes also cleaving in two di- 
rections parallel to the sides of an oblique and compressed 
four sided prism. These lamina, sometimes a quarter of an 
inch broad, are commonly collected into radiating or diver- 
