112 = Brush and Dana—Danburite from Russell, N. Y. 
realized, and the material which he has forwarded to us, as the 
result of his recent active explorations, is all that could be de- 
sired both as to quantity and quality. We take pleasure in 
acknowledging ae our indebtedness to him for his prompt- 
ness and liber 
Method of occurrence.—The mineral occurs both crystallized 
and massive, imbedded in what Mr. Nims calls a granitic roc 
the points at which it is found extend along the brow ofa hill 
for a considerable distance, say half a mile. The crystals line 
cavities or seams, sometimes of very considerable size, in the 
massive mineral or the enclosing rock. The associated miner- 
als are a pale green pyroxene, a dark brown tourfnaline, and 
also some mica, quartz and pyrite. Of these species, the dan- 
burite often encloses the crystals of pyroxene and tourmaline 
and is itself imbedded in the quartz, which is a point of inter- 
est in connection with its time of formation. These cavities 
were doubtless all filled srigwnely with calcite, as the facts ob- 
served conclusively pro ew perfectly fresh specimens 
were found with the ile imbedded in pink calcite and Mr. 
Nims believes that when the explorations are carried deeper 
that larger quantities may be obtained. is is much to be 
desired, for the perfectly ne and transparent crystals found 
in the calcite are of rare bea eauty. The specimens here spoken 
of ai ed actually obtained from some loose bowlders found on 
the 
The most of the specimens are now nearly or quite free from 
calcite, that mineral evidently having been removed by slow 
solution. The crystals are thus left in their original position 
projecting into me cavities. This natural removal of the cal- 
cite is in some aspects of the case an advantage, and in thas 
quite the reverse. In no other way could the crystals have 
been freed from the ae so perfectly and with so little injury 
to themselves ; for the mechanical removal is out of the ques- 
tion owing td. ‘the brittleness of the mineral, and the removal 
chemical means in the laboratory would not leave the erys- 
tals so nearly in their original condition. On the other hand, 
the specimens as found are somewhat destitute of a go of 
aspect, the crystals being much rifted internally and m 
moved. It is to be stated, however, that, while the mineral 
thus lost something of its original beauty, it is, in most ¢ sas 
very little if at all altered chemically, even the luster of the 
crystalline faces having suffered but little. On some few of 
’ the specimens, on the other hand, the aaah are quite opaque 
and have little luster. 
General crystallographic and physical characters.—The dan 
bnrite from Russell, as has been stated, is in part ceusieiliaed 
