Name. 
Chemical 
comp, ana 
reactions. 
Specific 
gravity. 
Cleavage. 
Usual combi- 
nations and 
form of see's. 
Twins 
Char. (End 
amount of 
d'bl refract 
Polariza 
tion 
colors . 
6. Apatite 
^3 ^12 
Cl Ca^ P3 
0 ,, FI. 
Dissolves 
in acids, 
gives phos- 
phoric 
acid reac- 
tion. 
3 16-3.22 
Crystals,, 
more rare 
ly granu- 
lar. Paral- 
lel 0 and 
I, incom- 
plete. 
Fracture 
II 0 very 
perfect, 
hence the 
needles 
are found 
broken in- 
to sections 
I, I and more 
rarely 0, gen- 
erally long 
columns. 
Not strong 
Usually 
not bril- 
liant, as in 
nepheline. 
\ 
i i 
(Al,) O3 
Insoluble. 
3 - 9-4 
R and oR. 
! 
i-2.oR. Rand 
grains. Hex 
agons and 
rectangles 
which are 
truncated at 
the angles by 
R. 
Rare 
in 
rocks. 
Strong. 
Very bril 
liant. 
i 
1 
I 
8. Toiir- 
maline. 
Complica- 
ted. Boric 
acid reac 
tion Not 
attacked 
by acids. 
3-059 
1 
Incom- 
plete R 
and i-2. i 
■Very com- 
plete frac- 
ture 1 oR. 
1 
Almost alw’ys 
crystalline R 
i-2.X (i-R-) - 
transverse sec 
tions triangles, 
hexagons non- 
agons. Often 
hemimorphic 
parallel to 
main axis, oR 
below, R 
above. 
Strong. 
Rather 
brilliant 
between 
red and 
brown. 
9. Specular 
Irott 
Fe, O3 
Easily sol 
able in 
HCl. 
5-19- 
5.28. 
1 
1 
i 
R.oR. 
Not char- 
l^acteristic 
in micro- 
scopic in- 
dividuals. 
1 
Tabular plates 
oR. i-2 and 
irregular 
plates. 
1 
i 
i 
1 
With 
axes 
paral- 
lel!. In- 
terpen 1 
etra- 
tion 
twins 
with 
re en- 
tering 
angles. 
Not defin- 
able on 
account of 
occur- 
rence. 
Very fee- 
ble. 
Minerals seeming to crystallize in the Hexagonal System. 
2 I SeeM onoclinic System- 
