216 



T. Schaller — Dumortierite. 



The macropinacoid occurs on all the crystals except the one 

 from Arizona. The reflections were poor but serve to identify 

 the form. The $ angles measured are as follows : 



90 c 



93 



90 



92 



91 



90 



02' 

 46 

 00 



57 

 15 

 16 



(Cal.) 



(N. Y.) 



Calc. 90° 00' 



The brachy prism I = go 2 = 120 occurs on four crystals, giv- 



Calc. (<j>) 29° 20' 



ing fair reflections. 



Meas. (<£) 30° 00' (Cal.) 



28 00 " 



29 22 " 



29 34 (N. Y.) 

 29 39 " 



The unit prism is poorly developed on the California crys- 

 tals, being present but once as a narrow face giving a poor 

 reflection. On the Arizona crystal it occurs twice as broad 

 faces. 



Meas. (</>) 48° 52' '(Cal.) Calc. (<£) 48° 20' 



49 16 (Ariz.) 



The macroprism g = Joo = 320 is present several times on 

 all the crystals except the one from Arizona. The measured 

 angles vary somewhat. 



Meas. (<£) 58° 55' (Cal.) 



Calc. (<£) 59° 19' 



59 



42 " 



60 



36 " 



59 



38 " 



59 



23 " 



60 



14 " 



59 



04 (N. Y. 



60 



07 " 



59 



25 " 



60 



23 " 



60 



31 " 



The macroprism n = 



= 2oo == 2 



reflections were fair. 





Meas. (<£) 65 c 



26' (Cal.) 



65 



35 " 



65 



19 " 



65 



12 " 



210 is present four timet 

 Calc. (<£) 66° 01' 



The 



The macrodome d — ^0 = 102 is present once on the Ari- 

 zona crystal. The reflections were not very good. The dome 

 v ~ 1 = 203 is present on one of the California crystals. The 



