Miscellaneous JVotices in Mineralogy, Geology, ^c. 233 



The only difference between the rock which has so re- 

 cently been wrought, and that which is commonly found is, 

 that it has a finer texture, and is capable of the highest pol- 

 ish — its hornblende being also diffused in a kind of porphy- 

 ritic manner. 



The mass from which it is taken lies upon the side of a 

 hill — in the form of a ledge, and may be split into slabs 

 without digging, or any similar difficulty. The quantity ap- 

 pears to be very considerable. 



We have received from Dr. B. L. Oliver, handsome pol- 

 ished specimens from Salem, some of which we are inclin'^ 

 ed to call Jasper ; those which we are told are called Por- 

 phyry at Salem, appear to be rather amygdaloid; the for- 

 eign imbedded substances are rather ovoidal, or almond 

 shaped concretions, than crystals ; the latter, imbedded in 

 some basis, being necessary to constitute a true porphyry. 



6. Microscopic crystals of Iron Pyrites. 



Extract of a letter to the Editor, dated Baltimore, Oct. 22, 1820. 



The object of the present letter is to send you inclosed, 

 some of the most minute, cubic and octahedral, and other varie- 

 ties of crystals of sulphuret of iron that I ever saw; they were 

 sent to this place from Scotville, Kentucky, as flowers of sil- 

 ver. I pronounced them at once to be pyrites, and thought 

 them powdered fragments, but the lens betrayed the crys- 

 tals, which are beautiful and well defined. I do not recol- 

 lect seeing in any cabinet such small ones, and I feel desi- 

 rous that you should possess a specimen. If you thinjf it 

 worth while to notice their discovery in Kentucky, you 

 can do so. I am very truly, yours, 



R. GILMORE. 



These crystals are singularly beautiful ; they are so mi- 

 nute, that they look like brass filings. — [-Ec?.] 



7. Limpid Quartz, from Fairfield, JVeio-York. 



Localities of quartz are innumerable, and even trans- 

 parent crystals are very common, but we have received 

 Vol. in No. 2. ' 30 



