Forms of Wagner ite. 135 



instance within half a degree. The parallelisms of edges ex- 

 hibited by the figure, as well as those depending on the in- 

 dices of the planes, but which cannot be shown by the draw- 

 ing, have been verified with the reflective goniometer. 



P, 7K = 109° 20' VI, m = 95° 25' 



b:/i::\ : 0-264. 



Plane angle of the base . . . . = 89° 1' 



Plane angle of the lateral faces = 108 37. 



P,/«* =116° 35' m, h} = 137° 42' 30" 



ASA*= 117 32 m,h^= 168 56 30. 



F,g' =102° 27' f,^= 57° 35' 



P,e^=161 23 30" P, ei = 146 3. 



V, ah =135 18 



P, 51=150 30 m,bh = lOO 10 bh, M = 138° 5S'. 



P, 6i=125 18 30" 7W,il = 125 21 30" bi,bi=108 49. 



P,«3=132 30" Wfla =116 18 30 ^, 03= 164 6. 



P, 03=112 45 7K, ^5 = 136 29 05,^5=117 39. 



P,C3=138 3 m,e., = 110 39 ^^^3=119 31. 



P,(i'rfig^)=114 30. m,{b'dig'')=133 6 g^(i' rf§ o^) = 143 32. 

 ^^,{b'd^g^) = 129 15. b\{b' di g^) = 160 32. 



The perpendicular drawn from the angle o on the opposite 



edge h meets it at a distance from a equal nearly to -^ . 



There is some indication of cleavage in a direction parallel 

 to the modification /^^ 



I took the specific gravity, and I found it, the water being 

 at a temperature of nearly 60°, equal to 3*01. Which agrees 

 very nearly with that obtained by Fuchs, which is 3-11. 



The fracture in a direction transverse to the prism is un- 

 even and splintery. 



It is easily scratched with a knife, and the streak is white. 



The colour, transparence, and lustre of the crystal I have 

 described, are perfectly similar to those of a Brazilian topaz, 

 with which substance, Wagnerite has been formerly con- 

 founded. 



The planes of the prism are strongly striated, with the ex- 

 ception of the planes g^. All the other planes are without 

 stria;, and more or less brilliant. 



The locality is the valley called Hollgraben, near Werfen 

 in Salzburg, where it is found in small veins of quartz in clay 

 slate. IJeutlant mentions the United States as another locality 

 of the same substance. 



XXXI. On 



