Proc. R.D.S., N.S., Vol. 5. 



Plate III. 



Fig. 3. 



Group of Iolite crystals removed from cavities in mixed Beryl and Orthoclase. Light Polarized. 



( X 18 diameters.) 



Fig. 4. 



Iolite in situ, showing marking of Orthoclase. 



Photo, from Nature, 



Photo-Ptd. by Forster & Co,, Ltd., Dublin 



