22 PROCEEDIN-GS OF THE NATIONAL MUSEUM vol.71 



Selected clear green crystals of this type were analyzed in the 

 Geological Survey laboratory by L. G. Eakins with the following 

 results : 



Analysis of vesuvianite 



SiOj- 37. 11 



AI2O3 19. 30 



Fe203 3. 31 



MgO 3. 89 



CaO 36. 24 



H.0 . 06 



F .58 



Total 100. 49 



8 9 



Figs. 8-9. — Crystals of Ve.suvianitb 



The specific gravity of the analyzed sample was 3.394 at 20°. 



Another type of vesuvianite of quite different appearance forms a 

 number of specimens, also from Italian Mountain. This is essen- 

 tially a vesuvianite rock made up of greenish yellow acicular prisms 

 of vesuvianite with interstitial calcite. The habit of one of the 

 prisms which was terminated is shown in figure 8. This rock grades 

 into patches of calcite in which small model-perfect brown short 

 prismatic vesuvianite crj^stals averaging 2 mm. in length occur with 

 small dodecahedral crystals of sulphur-yellow to greenish-yellow 

 garnets. 



A third and very unusual type of vesuvianite remains to be men- 

 tioned. Certain specimens showing large imperfect and somewhat 



