IRON. 405 



IIUDSONITE. 



Description. Colour black, often with a brownish tarnish. Streak green. It occurs mas- 

 sive, exhibiting one very perfect cleavage like some varieties of pyroxene. Lustre vitreous 

 to resinous. Opaque. Hardness from 4.5 to 5.0. Specific gravity 3.50. Alone before 

 the blowpipe, it fuses with effervescence into a black bead, which is attracted by the magnet. 

 This mineral, which is proposed as a new species, was found by Dr. Ilorton in a vein of 

 quartz in the town of Cornwall, Orange county. Its composition, according to my analysis, 

 is as follows, viz : 



Silica, 37 . 90 



Oxide of iron, 36 . 80 



Alumina, 12.70 



Lime, 11.40 



Magnesia, 1.92 



It agrees more nearly with the Pohjiitc of Dr. Thomson, than any other mineral with which 

 I am acquainted. He describes that species as being found in a bed, in magnetic iron ore, 

 at Hoboken in New-Jersey. Colour black ; composed of plates ; but one cleavage discerni- 

 ble. It resembles hornblende, or still more arfwedsonitc in its appearance. Hardness 6.25. 

 Alone it docs not fuse.* 



The composition of Dr. Thomson's mineral is as follows, viz : 



Silica, 40 . 04 



Protoxide of iron, 34 . 08 



Protoxide of manganese, 6. 60 



Alumina, 9.42 



Lime, 1 1 . 54 



Water, 0.40 



As it regards composition, the hudsonite differs in its not containing oxide of manganese, 

 for which it was carefully tested, and in its smaller proportion of lime. It strikingly differs 

 also in its hardness, and in the ease with which it is fused by the blowpipe. The jiowder, 

 which is green, has its colour heightened by the application of heat. 



Opposed as I am to the introduction of new species on slight grounds, it is with some hesi- 

 tation that the above name, in allusion to the river in the vicinity of which it occurs, has been 

 proposed for the mineral in question. But tlic characters which it exhibits seem to me to be 

 sufficiently important to warrant its separation. 



* Outlines of Mineralogy, Otology, i^-c. There is undoubtediy a mistake in regard to llii.> locality of this mineral as above 

 given. I am not aware of the existence of a bed of magnetic iron ore at Hoboken. Our mineral is in a ganguc of while quartx. 

 and has apparently not been exposed to admixture of any kind, except perhaps of silica. IJul the black hudsonite and wliilc 

 quartz are enliicly distinct in all the specimens which 1 have seen, and seem never to pass into each other. 



