T,' fa, e fage 69.] 



DICHROIT, IOLITE, CORDIERITE, 



ORTHOEHOMBIC. 



OUTHORHOMBIC. 



I l\I= 119° 10' and 60° 50' 



I A i-3 = 150° i-i A i-3 = 150° 25' 



i-S A i-3 = 120° 50' O A 1= 90° 



Cleavage, i-i distinct ; i-i and O indistinct. Fracture, sub-conchoidal. 

 Crystals, foliated parallel 'with O. Twins, composition face 7". 



Transparent. 

 Dichroic, blue to yellow, but feeble in small crystals 



Lustre vitreous. 

 Colour, blue shades. 



Spec. grav. ;= 2-59 



Hardness d 7-7'5 

 Fuses at 5 - 5, loses iransparency. 



Fig. 1. 



Fig. 3. 



Fig. 5. 



Transparent. 

 Dichroism uncertain. 



Lustre vitreous. 

 Colour, pale blue. 



Spec. grav. = 2-58 



Hardness about 7. 

 Fuses with Iolite, turns opaque white. 



Analysis of Impure Specimen. 



56-7 

 20-7 

 13-9 



4-2 

 trace 

 trace 



2-0 



Fig. 6. 



97-5 



