200 
NEPHRITE CELT 
York, (a =1.5992, yt= 1.6246) and from Lee, Massachusetts 
(a =1.6022, y= 1.6347), which were analyzed by Stanley.® 
A chemical analysis of the material of the Paraguassu celt, 
with the results is shown in No. 1 of Table I. Phosphorus and 
chromium were especially looked for, but not a trace of either was 
found. The green color must, therefore, be due to the presence 
of ferrous and ferric oxide. Fluorine was not determined be¬ 
cause of the very small amount of material. The water was 
weighed directly by Penfield’s method. 
I. ANALYSES OF NEPHRITE AND TREMOLITE 
1 
2 
3 
4 
5 
6 
SiOa . 
59.79 
54.76 
62.86 
58.22 
57.45 
57.69 
TiOte . 
0.23 
n. d. 
n. d. 
n. d. 
n. d. 
0.14 
AkOa . 
0.88 
4.081 
1.37 
1.30 
1.80 
Cr203 . 
none 
• • • « 1 
* • • « 
• • • • 
• • • • 
FezOa. 
0.33 
n. d. [ 
7.24 
0.04 
0.18 
0.00 
FeO . 
0.96 
1.80 j 
0.61 
0.22 
0.55 
MnO . 
0.10 
n. d. 
n. d. 
0.04 
0.07 
trace 
MgO . 
24.31 
21.26 
12.87 
23.97 
24.85 
24.12 
CaO . 
12.52 
14.31 
12.32 
12.95 
12.89 
13.19 
NaaO . 
0.35 
n. d. 
4.19 
0.24 
0.67 
0.48 
KsO . 
0.06 
n. d. 
trace 
0.04 
0.54 
0.22 
H 2 O+ . 
2.10 
3.72 
0.57 
2.17 
1.16 
1.56 
H 2 O— . 
0.32 
• • « • 
« • • • 
• « • • 
0.09 
0.10 
F 2 . 
n. d. 
n. d. 
n. d. 
0.17 
0.77 
0.37 
P 2 O 6 . 
none 
0.40 
n. d. 
• • • • 
• • • • 
• • • • 
99.95 
100.33 
100.07 
99.75 
100.19 
100.22 
Sp. gr. 
2.938 
2.980 
2.997 
2.980 
1. Nephrite celt, Rio Paraguassu, Bahia. Washington analyst. 
2. Nephrite pebble, Amargoza (Baetinga), Bahia. Hussak, op. cit, p. 91. 
3. Nephrite celt, Philadelphia, Minas Geraes. Scheldt analyst. Fischer, 
op. cit., p. 215. 
4. Tremolite, Switzerland. Kreuz analyst. Kreuz, op. cit., p. 213. 
5. Tremolite, Richville, New York. Stanley analyst. Penfield and Stan¬ 
ley, op. cit, p. 31. 
6. Tremolite, Lee, Massachusetts. Stanley analyst. Penfield and Stan¬ 
ley, op. cit., p. 32. __ 
The Paraguassu nephrite is evidently a very pure tremolite, as 
is shown by the close similarity between its analysis and the 
three analyses of well crystallized, pure tremolite given in Nos. 4, 
5, and 6. In all of them, it may be noted, the ratio SiOg,* 
(R", R'2)0 is very close to unity, if H 2 O+ and Fg are reckoned 
6 Amer. Jour. Sci., (4), Vol. XXIII, pp. 31-32, 1907. 
