150 



[ Senat^i 



Cleavage perfect, very distinct in the direction of the short diagonal ; 

 indistinct approaching distinctness in the direction of the long diago- 

 nal ; hemiprismatic in fragments. Fracture uneven to conchoidal and 

 hackly. Hardness 6. Specific graYity=2*609 to 2*620. Translucent 

 in thin laminae to transparent. 



The oblique cleavage in the direction of the long diagonal is charac- 

 teristic of loxoclase, although not always very distinct ; hence its name. 

 The sp. gr. is also higher than any other of the orthoclastic feldspars. 

 It appears subject to decay by exposure to the atmosphere. 



Composition. (Mean of two analyses,) silica'^63 * 50 ; alumina 20*29 ; 

 oxide of iron 0-67,- potash 3-03; soda 8-76; lime 3*22; water and 

 fluoride of silicon 1*23. Fuses before the blowpipe with difficulty* 

 Heated in a glass bulb it gives out a little water and fluoride of silicon, 

 and is very imperfectly decomposed by hot muriatic acid. Poggeri' 

 dorff's Annalen; PhiL Mag. ^ An7i.y xxix., p. 150, Aug.^ 1846. 



MONAZITE. 



This mineral, associated with sillimanite, as at Chester, Norwich and 

 Saybrook, Conn., has been found in a quarry in Yorktown, Westches- 

 ter county, by Mr. J. Mekeel. The monazite is in very perfect, trans- 

 parent prisms, with a simple pyramidal termination ; the crystals are 

 small, rarely exceeding one-eighth of an inch in length, and are scat- 

 tered like small garnets through the brown quartz adjoining the mag- 

 netic iron ore which is an associate of this mineral. Sill. Jour, xlvi, 

 p, 207. 



NITRATE OF LIME. 



This is said to be found in Marbletown, Ulster county, and near 

 West Point, Orange county. Mather^s Rep. on the Geol. \U Dist,, 

 p. 85. 



PHYLLITE. 



This is a mineral which was first found by Vanuxem, in the town of 

 Newport, Rhode Island. It is in the form of black shining scales, in 

 slate. I have found the same near the Clove iron mine, in Dutchess 

 county. 



Composition. According to Dr. T. Thomson, the constituents of 

 phyllite are as follows: silica, 38*40; alumina, 23*68; peroxide of 

 iron, 17*52; magnesia, 8*96; potash, 6*80; water, 4*80. 



It is thought to be identical with the ottrelite of Desclozeaux and 

 Damour ; but Thomson's name has the priority. 



