440 



DESCRIPTIVE MINERALOGY. 



LOCALITIES. 



This mineral, which in its crystalline form is yet very rare, is found in the form of a thin 

 crust or efflorescence, covering the sides of the shaft and timbers of an old mine of arsenical 

 pyrites, four or five miles northwest from the village of Carmel in Putnam county. It only 

 appears where the shaft and timbers have been covered by water, and it is undoubtedly the 

 product of the partial decomposition of the arsenical pyrites, which has here been found in 

 considerable abimdance. 



ORDER X. CERIUM, 



1. Allanite. 



ALLANITE. 

 [In honour of Mr. Allan, the Mineralogist, who first noticed it.] 



Allanite. Cleaveland, Pkittips, Tkomson and Shepard. — Variety of Cerine. Beudant. - 

 Ore. Jamestm. — Tctartoprismatisches Mclan-Erz. Mohs. 



-Anortbitic Melane- 



Fig. 533. 



Description. Colour black inclining to green, grey, or brown. 

 Streak greenish or brownish grey. It generally occurs massive, but 

 is sometimes crystallized in oblique four-sided prisms, variously ter- 

 minated. P on M about 115°. Cleavage perfect parallel to M and 

 M r. Fig. 533 (from a crystal brought from Greenland.) Fracture con- 



choidal. Lustre imperfect metallic. Opaque. Brittle. Hardness 

 from 5 . 5 to 6 . 0. Specific gravity from 3 . 20 to 3 . 60. Before the 

 blowpipe, it melts with intumescence into a brownish or blackish 

 mass; with borax, it melts into a black opaque globule. It gelati- 

 nizes when treated with muriatic acid. 



Composition. Protoxide of cerium 21.60, protoxide of iron 15.10, silica 33.02, protoxide 

 of manganese 0.40, alumina 15.23, lime 11.08, water 3.00 {Stromeyer). 

 The Cerine and Orthite of Berzelius, are supposed to be identical with this species. 



Geological Situation. Allanite was first found at Alluk, near the southern extremity of 

 Old Greenland. The variety named Orthite occurs in quartz at Finbo, near Fahlun in Swe- 

 den ; in granite at Skeppsholm ; and also at Lindenaes in Norway, and in Greenland. 



