288 A. H. Chester—Mineralogical Notes. 
This is evidently pectolite, as is probably much that is now 
called okenite from the same locality. The specimen examined 
is made up of a mass of fine interlaced fibers, pure white in 
color, with a sub-pearly luster, and forming a layer about an 
inch in thickness. 
6. HEMIMORPHIC CRYSTALS OF BARITE. 
The crystals of barite from DeKalb, St. Lawrence Co., N. Y., 
described by G. H. Williams,* exhibit the following macro- 
domes besides the one he mentions: 1-7 (d), $-7 and the rare 
one #-7(w). The crystals are generally so grouped together that 
one doubly terminated cannot often be obtained, but a study 
of the few that have been observed shows them to be hem1- 
morphic and quite different from any heretofore described. 
The crystals are all alike and have the form given below; fig. 1 
shows one in the usual position, while in fig. 2 the brachy- 
2. 
diagonal is made vertical. Measured with a hand- goniometer 
OA$-7 (cAw) is found to be 188°, corresponding closely with 
the angle given by von Kokscharow,+ 132° 58’ 25’. As men- 
tioned before, all the doubly terminated crystals found show 
this dome on one ‘end, and it is also quite often seen on the 
broken and grouped crystals which show but one termination, 
though the face $-7 (d) is rather more common. A few singly 
-terminated crystals were found with both domes. Im these 
cases the curious alteration noticed by Williams is well shown, . 
the faces 3-2 being changed to the chalk-like material which he 
describes, while the next face, 4-7, is colorless and transparent, 
or sometimes altered on the edges, leaving a triangular spot of 
unaltered material in the center of the face. It is worthy of 
notice that this form, so rarely seen heretofore, should be so 
common in this one locality. 
* Johns Hopkins Univ. Circ., No. 29, p. 61, 1884. 
+ Min. Russl., vii, p. 54, 1875. 
