$22 Mr W. H. Keating'^s Jccount a nexv Mineral 
Class I. — Order SPAK. 
Genus, Augite Spar. 
Species, Polystome Angite Spar. 
Prismatic. P, unknown. Cleavage F-f x — lOO'". Hrr:4.5. 
0=3.51—3.60. 
But until Mr Mohs’ system he more generally known and 
approved of, it may be proper to give this mineral a name un- 
connected with his arrangement. Accordingly, Mr Vanuxem 
has proposed to dedicate this mineral to Mr Jefferson; I have 
readily assented to this proposal, and we now offer this mineral 
to the public under the name of The Jeffersonite. 
This mineral has hitherto been found in too small a quantity, 
to offer any utility in the arts. Should it, however, be found in 
sufficient abundance, it would become valuable as a flux for the 
iron-works in the vicinity. The absence of magnesia, and the 
abundance of manganese, seem to make it very valuable for this 
object. 
The Jeffersonite presents some points of resemblance with 
the Pyroxene of Haiiy, but still it can be well distinguished 
from it. Its cleavages are essentially different from those of the 
Pyroxene, but appear to approach some of the faces of crystals 
of substances which have been united to this species : for in- 
stance, the angles in the Diopside (Mussite and Alalite), Fas- 
saite, and in the Pyroxene anahgique^ come very near some of 
the angles of cleavage obtained in The Jefiersonite. I at first 
indulged the idea, tliat these cleavages might be considered as 
cleavages parallel to the faces of secondary crystals of Pyroxene, 
but upon reflection l am fully convinced that this is not the case; 
for the angles which we have measured, cannot be deduced from 
the others by a strict mathematical calculation, and though they 
may approximate, they are not the same. Besides, no analogy 
can warrant us in admitting, that the regular cleavages of one 
substance can disappear entirely, and be replaced by cleavages 
parallel to secondary crystals. On the contrary, wherever mine- 
rals have been found presenting different orders of cleavage, the 
first, or those parallel to the primitive form, were always predo- 
minant: Thus, in carbonate of lime, it is not uncommon to meet 
the cleavage parallel to the equiaxe^ but I believe in every in- 
stance the primitive is predominant. In a rarer and more in^ 
