478 T. L. WATSON WEATHERING OF ALLANITE 



of allanite in South Carolina is 4^^ miles east of Iva, Anderson Coimty.^^ 

 The allanite conies from a shallow opening made for gold in a very coarse 

 pegmatite composed chiefly of grayish qnartz, with a little mica and not 

 very much feldspar. From the same opening were derived pyroxmangite 

 (manganese pyroxene), a new member of the pyroxene group, and its 

 alteration product, skemmatite, a black oxide of iron and manganese, 

 recently described by Ford and Bradley.®* Scattered over the surface in 

 the immediate vicinity of the hole are pieces of an unknown mineral, 

 probably an altered pyroxene, ranging in size from small fragments up to 

 masses probably 50 pounds in weight. Several hundred yards to the 

 south are found zircon crystals, good cleavage fragments of corundum, 

 and limonite pseudomorphs after pyrite. 



The black, vitreous mass of allanite from this locality exhibits the 

 usual deep reddish brown crust derived from the fresh mineral by weather- 

 ing and has afforded excellent material for study. The powder is soluble 

 in hot dilute HCl with the separation of gelatinous silica; is infusible 

 before the blow-pipe and non-magnetic; yields water when heated in 

 closed tube which reacts neutral; and does not react for carbonates. 



ANALYSES OF ALLANITE FROM VIRGINIA AND NORTH CAROLINA 



For purposes of comparison eight analyses of allanite from different 

 localities in Virginia and jSTorth Carolina are tabulated below in order of 

 decreasing silica. Attention need only be directed in the analyses to the 

 following features in the composition of the mineral from these States : 

 (1) Predominance of ceria over the oxides of the other metals (lanthanum 

 and didymium) belonging to the cerium group in six of the analyses 

 with didymia in largest amount in analyses I and V. (2) Absence of 

 the metals of the yttrium group in four (Virginia) of the eight analyses 

 and the presence of these in each of the three analyses of the N"orth Caro- 

 lina mineral, ranging in amount up to nearly 2 per cent (I). Unusual 

 richness of analysis VIII (Virginia) in the oxides of the cerium metals 

 (51.13 per cent, more than double the usual amount), especially in eerie 

 oxide (33.76 per cent), which are the maxima for any analysis of the 

 mineral yet recorded. When compared with the other eighty-four 

 analyses of allanite listed by Hintze,®° the Virginia mineral (VIII) con- 

 tains nearly 6 per cent more of eerie oxide than the maximum one (28.19 



=3 The locality is a new one for allanite. It was visited about five years ago by Mr. 

 George L. English, of Rochester, New York, who first identified the mineral as allanite, 

 and who recently very kindly placed an excellent specimen of it at the writer's disposal. 

 The writer makes further grateful acknowledgment to Mr. English for some unpublished 

 notes on the locality on which the above statement is based. 



5* W. E. Ford and J. H. Bradley : Am. Jour. Sci., vol. xxxvi, 1913, pp. 169-174. 



55 C. Hintze : Handbuch der Miueralogie, 1897, pp. 272-276. 



