1922] 



NATURAL SCIENCES OF PHILADELPHIA 



107 



b (010) show some oscillation, giving raise to characteristic 

 striations on the latter form. This type shows great irregularities, 

 due to parallel growth with other individuals. 



Type III (figure 3) was seen on some microscopic mounts. The 

 tops of the crystals show a small crater with a jagged edge; the 

 inner faces of which are irregular, and apparently curved. Ensconced 

 in the crater is a small pyramid, probably f (121). The form b 

 (Oil) is horizontally striated. 



The polar elements, p Q and q were calculated from the average 

 angles of the forms d (101), h (021), e (111), f (121), 1 (131), m (110) 



Table I. Angle Table of Glaucochroite 



a:b :c=0,4606:l : 0.5899 

 p = 1. 2806; q = 0.5899 



Letter 



Symbol 

 Miller Gds. 



No. of 



faces 



Measured 



9 ? 



Calculated 



cp p 



b 



a 

 m 



-z 



*d 

 x 



*k 

 h 

 e 

 f 



*1 



00 00± 4 

 90 02± 7 

 65 13±11 

 47 18±19 

 36 28±51 

 32 12 

 90 03± 6 



00 18±16 

 00 03 ± 5 

 65 14±39 

 47 19± 6 

 35 52± 7 

 47 04 



90 00±10 

 89 54± 6 

 89 57± 6 

 ^0 04± 7 



89 39 ±26 



90 16 



51 55± 7 



30 22± 6 

 49 56± 5 

 54 44 ±24 

 60 12 ±14 

 65 23 ± 6 

 41 02 



00 00 

 90 00 

 65 16 

 47 21 

 35 53 

 31 49 

 90 00 

 90 00 

 00 00 

 00 00 

 65 16 

 47 21 

 35 53 

 47 21 



90 00 

 90 00 

 90 00 

 90 00 

 90 00 

 90 00 

 52 01 

 23 07 

 30 32 

 49 43 

 54 39 

 60 OS 

 65 24 

 41 02 



New forms marked * 



and s (120). The axial ratios were obtained from these values. 

 The results are not concordant with those of Penfield and Palache : 



a :b :c = 0.440 : 1 

 .4409 : 1 

 .4606 : 1 



0.566 (Penfield) 

 .5808 (Palache) 

 .5899 (Gordon) 



