264 Account of some new Vesuvian Minerals. 
that of chondrodite is yellow, or brownish yellow. Finally, 
the infusibility of Christianite distinguishes it from all zeo- 
lites, from Nepheline, felspar and amphigene. 
BioTina. 
This was at first confounded with the last mentioned min- 
eral, and is separated from the conviction that its figure can- 
not be derived from the primitive form of that mineral. It is an- 
nounced as new to draw the attention of mineralogists to it, 
and to the series of Vesuvian crystals which belong to this 
species, and which distinguishes it from all hitherto found on 
this volcano, by its limpidity and splendour—by its infusibili- 
ty, and by its system of crystalization. The name is propo- 
sed in honour of Biot, a distinguished French naturalist, 
well known for his attainments in the physical sciences. 
: cific characters. 
Geometrical Characters. The primitive form is an ob- 
tuse rhomboid—(fig. 212.) The angle of P with P’ is 94°, 
and that of P and the opposite face is 86°. The other an- 
gles are aes 20’ and 65° 40’. The face AE is rather lar- 
ger than AE 
Physical Chenille Sp. gr. 3.11. Ht scratches glass 
—lustre very vivid—fracture vitreous, tending to conchoi-. 
dal. Fragments angular and irregular. All the ran 
= double refraction, as was verified by Mr. Biot a 
ap 
Chemical Characters. The acicular ashe held for a 
tong time in the flame of the blowpipe were unaltered. Ni- 
tric oon Cee dissolv res it without ebro a jelly. 
ves. 1. Bis-marginate—(fig. 213.) 2. age re 
Geleal—(Gy. 214.) 3. Sei-duodecimal—(fig-. 215-) 
Octo-duodecimal—(fig. 216.) 5. Octo-sestecimal (ie 
217.) 6. Amphi-hexahedral—(fig. 218.) 7 champloo 
hedr cdval=-(lg: 219.) 8. Quadri-duodecinal—(fig. 2 20.) 
