68 Scientific Intelligence. [July, 



V. Necronite (a supposed new Mineral).* 



Extract of a Letter from Dr. H. H. Hayden, of Baltimore, to 

 Dr. Silliman, dated Jan. 5, 1819. 



" It (the necronite) occurs in a primitive marble, or limestone, 

 which is obtained 21 miles from Baltimore, and a small distance 

 from the York and Lancaster road. It was first noticed by 

 myself at Washington's monument, in which this marble is prin- 

 cipally employed. 



" It occurs, for the most part, in isolated masses in the blocks, 

 or slabs, both in an amorphous and crystallized state. It is most 

 commonly associated with a beautiful brown mica, of the colour 

 of titanium; small but regular crystals of sulphuret of iron, tre- 

 molite, and small prismatic crystals of titanium, which are rare. 

 The form of the crystals is a rhomboid, approximating very much 

 to that of the felspar, and which has inclined some to consider it 

 as such. Also, the hexaedral prism, resembling that of the 

 beryl. This form is rare, and has not as yet, I believe, been 

 found complete. Its colour is a bluish white, and clear white. 

 Its structure much resembles felspar, being lamellar ; sometimes 

 opaque, semi-transparent and transparent, at least in moderately 

 thin pieces. It scratches glass, carbonate of lime, and even fel- 

 spar, in a slight degree. In all our efforts, it has been found 

 infusible, per se, or with borate of soda ; and even from all the 

 force of heat that could be excited in a smith's furnace, it came 

 out unchanged in any degree. The acids seem to have no 

 sensible effect upon it, either cold or hot. This is all that I can 

 say of it at present, except that it possesses a most horrid smell.t 

 I have since found in a marble of the same kind, but from a 

 different quarry, and a few miles distant from the first, a quartz 

 almost as fetid as the necronite, and likewise associated with 

 small prisms of titanium. 



" These substances carry with them a degree of interest in 

 another point of view. They seem to invalidate the opinion that 

 the fetid smell of secondary limestone, slate, &c. is derived from 

 the decomposition of animal matter, as their gangue is decidedly 

 a rock of primitive formation." 



Another new Mineral observed by Dr. Hayden. 



" Exclusive of the interest which the necronite has excited 

 with me and several others, I have besides stumbled upon 

 another substance, if possible, still more interesting. I disco- 

 vered it in an imperfect state, about four years since, but not 

 until recently have I been able to find it perfect, in beautiful gar- 

 net-coloured cubic crystals one quarter of an inch square, or 

 nearly. These crystals are very liable or subject to decomposi- 

 tion, in which state they present a perfect but spongy cube. 



» From Silliman's American Journal of Science, i. 306. 



+ On account of its peculiar cadaverous odour, Dr. Hayden proposes to call 

 this mineral (should it prove to be a new one) Necronite, from the Greek Nsxjof. 



