336 
DESCRIPTIVE MINERALOGY. 
Fig. 306. 
resemble the prismatique of Hauy. Fig. 306. M on l 120° ; P on l 
111 0 40b 
The variety necronite, in translucent crystals, usually imperfect, is 
also found at this locality. It is very fetid when rubbed briskly, or 
when struck with a hammer. 
About five miles north of Ticonderoga, in Crown-Point, good clea¬ 
vages of red feldspar have been obtained. The associates are quartz 
and magnetic iron ore. 
In Newcomb, it occurs, according to Dr. Emmons, of a green colour. 
To these localities several others might be added, as there is scarcely 
a mine of magnetic iron ore at which feldspar is not found, either as 
an associate of the ore, or forming a part of the rock in the immediate vicinity. But I have 
never observed it in these situations exhibiting regular crystalline forms, although it is often 
susceptible of cleavage. 
Herkimer County. Fine cleavages of feldspar of pale flesh-colour, may be obtained on 
the banks of the canal in the immediate vicinity of Little-Falls. Other common varieties also 
occur in the gneiss near this village. 
Jefferson County. A valuable bed of whitish feldspar occurs on High island, in the St. 
Lawrence, nearly opposite to Alexandria. It is said to be suitable for the manufacture of 
porcelain.* 
Lewis County. Near Natural bridge, feldspar, 
both crystallized and massive, is found in white 
limestone. The crystals have a white and yel¬ 
lowish white colour, and are from a quarter to 
three-quarters of an inch in length. They are 
associated with pyroxene and hornblende. Among 
the forms are the prismatique of Hauy (Fig. 306); 
and also the modifications represented in Figs. 
307 and 308. M on l 120° ; P on l 111 0 40'; P 
on s 124° 10 / ; P on y 99° 29' {Hauy). 
The massive variety often has a bluish colour, and is associated with the black pyroxene, 
scapolite and sphene, for which this locality is so much celebrated. 
New-York County. At Thomson’s quarry, near 196th-street (Kingsbridge), necronite or 
fetid feldspar is found in the white limestone. It is bluish white, and is very fetid when struck. 
At Harlem (30th-street and 9th avenue), small crystals of feldspar, of the primary form, 
are found in the fissures of gneiss. There is also a six-sided prism formed by the truncation 
Fig. 307. Fig' 308. 
Emmons. New-York Geological Reports, 1837. 
