AKT. IS MINERALS OF ITALIAN MOUNTAIN CROSS AND SHANNON 19 



Measurements of sahlite crystal, Figure 5 



Another sin^de specimen (No. 84580) from Taylor Peak has 

 what apparently is altered diorite for a base with euhedral crystals 

 of vitreous blackish-green pyroxene projecting into a mass of stil- 

 bite and scolecite. The pyroxene crystals are all broken and show 

 no terminations remaining. The remnants of crystals reach 15 by 

 40 mm. in size. Under the microscope the crushed pyroxene is fresh, 

 pale blue-green and nonpleochroic. It is biaxial positive with 2V 

 medium large, dispersion r < v weak to marked. The extinction is 

 Z A c=41° maximum measured on cleavage fragments. The refrac- 

 tive indices measured are: a =1.682, ^=1.697, 7=1.713. 



VESUVIANITE 



Vesuvianite is one of the most interesting and attractive of the 

 minerals occurring at Italian Mountain and constitutes very excel- 

 lent mineralogical specimens containing well developed crystals, some 

 of which reach fairly large size. With the possible exception of 

 Crestmore, California, and one or two Maine localities, no place in 

 America has heretofore furnished such fine specimens of this mineral 

 and the specimens from the other localities mentioned are distinctly 

 different in habit, color, and associations. 



The most abundant type of vesuvianite represented in the collec- 

 tion occurs in crystals of transparent yellowish olive-green color 

 varying gradually in habit from bipyramidal to short prismatic. 

 These are found either singly or in groups or crusts implanted on 

 the walls of open spaces in a dense garnet-diopslde hornfels. The 

 limits of variation in crystal dimensions are illustrated in Figures 

 6 and 7. Figure 6 exposes the commonest habit— bipyramidal with 

 the dominant form the unit pyramid ??(111), the prismatic faces be- 

 ing greatly suppressed. A small crystal of this habit gave the fol- 

 loAving measurements : 



