Minerals from New Holland. 311 
tion. ing cleavage, however, is. obtained xit great 
, as pu case with this mineral from other 
rupted - cross fracture. There are also transverse 
strie on some of the crystals parallel with the opposite 
cleavage, appearing very rarely upon the aeuminating 
faces.. The larger crystals, which are nearly of the 
size of the last figure, are of a grayish white color, and 
nearly opake ; the smaller are colorless and transparent. 
These crystals are highly axotomous, the folia sepa- 
rating with great readiness parallel to Pj and the 
faces of this cleavage present a high pearly lustre, 
though not superior to that of some of the faces of 
crystallization in the same direction. Faces. M, M, 
vitreous, some smooth and shining, others roughened 
and dull. Faces a, a of the pyramids, with few ex- 
ceptions, perfectly smooth and brilliant, pearly. The 
proportion between the length and breadth of these 
crystals is. variable; but, in the smaller, and most per- 
fect ones, it is not less than four to one. ~ 
The other crystals of apophyllite alluded to, are of 
` greater dimensions, measuring frequently an inch 
through the vertical axis of the prism. "They are 
derived from a square prism; scarcely distinguishable, 
in the comparative length of the lateral and basal 
edges of the crystal, from à cube, and present only 
simple replácements on the solid angles, by perfectl y 
smooth and brilliant planes of a high pearly lustre, 
resembling specimens in the writer's collection from 
Iceland.* . The lateral faces are frequently composed 
"^ ie" in my possession (from Nova Scotia) several large and 
transparent crystals of this mineral, of which several from one local- 
a 
ty 
E 
