248 WRIGHT—CRYSTALLOGRAPHIC PROPERTIES. (June 1, 
MoHAWEKITE. 
The artificial crystals of mohawkite are extremely small, and not 
so well developed as those of the domeykite. On the goniometer 
their faces exhibit unclear, manifold reflexion signals which render 
an exact determination of the element impossible. The measure- 
ments indicated again the holohedral division of the hexagonal 
system. 
Observed forms : 
Letter: c a 6b 
z v p 
Symbol Goldschmidt. . 0 we) 0 0 20 10 20 
Bravais...... OOO IIZo 1070 20273 I07I 2091 
Element : Po = 1.001 + 0,008 
2A e =ai ia EOr 
2: Cy = 1: 0.867 
The element was computed from the mean of all usable angles. 
Possibie error + 14’.. The marked variation in the angles was due 
to the poor quality of the crystal faces. A careful search through 
the entire material showed that not one of the faces was perfectly 
even. The dimensions of the crystals are so small that the observer 
is unable to judge, even with the aid of a pocket lens, accurately as 
to the quality of the faces. The individual forms exhibit a sharp 
outline but an uneven, rolling surface. On the goniometer, after- 
wards, these characteristics are only too noticeable. 
Table of Angles. 
¢==1/501 lg c—017656\lg ay—006247 lz fy 000043 @=1/154|f,—1/001| (G.) 
Let-| Sym-| Bra- £ s a dad 
Vo, EPS be Sas @ p So IN & ” | (Prisms) y =tgp 
(¥: y) 
° ° ° ° ° ° ° 
I & fo) ooo! | — | 0,00} 0.00} 0.00) 0.00} 0.00} 0/5773 ° ° 
2 a ro) I1ZO |30.00|90.C0} 0.00/90.00] 30.00|60,00 ° or 0 
a é 0 | I0TO | 0.00|90.00|g90.00/90.00} 0.00|90,00 fo) oo oo 
4 z 20 | 2023) 9.00)33.47| 0.00)33-47) 0.00) 33.47 fo) 0/669; 0/669 
5 v 10 | IOZI | 0 00)45.02) 0.00/45.02) 0.00/45.02 fo) 1/OOI| 1/001 
6 p o | 2071 | 0.00/63.27| 0.00/63.27| 0 00/63.72 fo) 2/002] 2/002 
