OASSITERITE CRYSTALS. 75 



The forms present are s (111), e (101), z (231), and the 

 prisms a (100), m (110), B (570), r (230), Ji (120) and (130). 

 This last mentioned form is referred to by Hintze 1 and is 

 very unusual. Readings obtained for </> (130) were 18° 21' 

 and 18° 27', as compared with the calculated jangle 18°26.' 



MANDOIE STATION, ASHFORD DISTRICT. 

 (Figs. 11, 12.) 

 The crystal illustrated is one of two fine specimens from 

 this district kindly placed at my disposal by Dr. Anderson. 

 The crystals are similar; the larger measures 8 mm. in 

 diameter, and the smaller (the one described here) is about 

 half this dimension. 



This crystal supports at one end a very small segment 

 in twin position according to the usual law, but this is so 

 small as to admit of an almost complete development of 

 the larger crystal. The faces of the larger crystal are 

 smooth and well developed, giving excellent reflections, 

 and measured and calculated angles are in close agreement; 

 those of the smaller segment, however, give distorted 

 reflections and unreliable readings, hence the dotted lines. 



The crystal is doubly terminated; the pyramids s (111), 

 z (231), and e (101) are prominent, and the prism zone is 

 reduced to a few small faces a (100), r (230), h (120) and 

 m (110), and at times these too are absent. Thus the 

 crystal has a strikingly bipyramidal habit. A curious feature 

 is the fact that the two z (231) faces near the broken portion 

 of the crystal, marked z" and z" respectively, have replaced 

 each other, thus giving that part of the crystal an unusual 

 aspect. A table of angles has not been appended for this 

 crystal, as it was thought unnecessary. 



Summary. — All the crystals taken from the hand specimen 

 of felspathic vein material, were remarkably small, aud 



1 Hintze : Handbuch der Mineralogie, Vol. i, 1902, p. 1679 



