436 



DESCRIPTIVE MINERALOGY. 



APPENDIX. 



It was several years since suggested by Mr. Brooke of London, that some of the minerals 

 which had been commonly ticketed Sphene, differed from that species, and should constitute 

 a new one. This supposed new mineral was first found at Phillipstown in Putnam county, 

 by Dr. Joseph Barratt. Since that time it has been found by Dr. A. F. Holmes of Montreal, 

 at Grenville in Upper Canada ; and more recently in Lewis county, near Natural bridge. 

 The same mineral, probably, also occurs in various parts of Orange county. 



In a recent paper by Prof. Shepard, in which he notices some localities of the above mine-. 

 ral, he proposes for it the name of Lederite. This name, however, was previously applied 

 by Messrs. C. T. Jackson and Alger to a supposed new species from Nova-Scotia ; and 

 although the latter has been thought to be identical with Gmelinite, it will probably retain the 

 name given to it, and thus introduce confusion. 



The mineral aUied to Sphene has a chocolate brown, light brown or dark clove colour. It 

 occurs regularly crystallized and massive. The primary form is an oblique rhombic prism, 

 whose bases are oblique from an obtuse edge. M on M' 112° 10'; P on M 115° 30'. Lus- 

 tre vitreous, inclining to adamantine. Semi-transparent to translucent. Hardness from 5.5- 

 to 5.7. Specific gravity from 3.33 to 3.57. Before the blowpipe, it exhibits the same 

 characters as sphene.* 



This mineral has not yet been analyzed, and the only known difference between it and 

 sphene is in the crystalline form. It must, therefore, be left to future observation to deter- 

 mine whether it is entitled to the rank of a species . 



WARWICKITE. 



[From its being found in the town of Warwick, Orange county.] 



Fig. 529. 



Warwlckite. Shepard {Artier. Jmr. of Science. XXXIV. 313). 



Description. Colour dark hair-brown to iron grey. It occurs 

 regularly crystallized. Primary form an oblique rhombic prism. 

 Fig. 529. M on M' 93° to 94°. Cleavage parallel with the longer 

 diagonal perfect. The cleavage planes thus obtained are finely stri- 

 ated vertically, and exhibit very distinct oblique cross cleavages. 

 Fracture uneven. Lustre eminently metallic, pearly ; of a copper 

 red colour on the perfect cleavage faces ; in other directions, only 

 vitreous in moderate degrees. Opaque except in very thin fragments, 

 when it is translucent. Brittle. Hardness from 5.5 to 6.5. Spe- 

 cific gravity, from 3.0 to 3.14. Before the blowpipe on charcoal, it 

 is infusible, but becomes of a lighter colour ; with borax, it dissolves 



* Shepard. American Jovmol of Sdenee, XL. 35T. 



