210 TJNIVEESITY OF VIRGINIA PUBLICATIONS 



oxide. When fresh the folia are soft and flexible, have pronounced greasy 

 feel and pearly luster, and show basal cleavage. One specimen shows, in 

 addition to the fine sugary quartz of the enclosing rock, clear and trans- 

 parent quartz in larger grains, which are regarded as indicative of forma- 

 tion from solution. Specimens of pyrophyllite in vein quartz collected 

 from Graves Mountain are on exhibit in the State Museum in Atlanta. 

 A part of the central portion of a second specimen was occupied by a sponge 

 of iron oxide, indicating the presence originally of some mineral other than 

 pyrophyllite removed by weathering and yielding the iron oxide. 



In addition to the vein-like occurrence of pj^rophyllite, the mineral is 

 frequently distributed through the quartzite in small particles and large 

 masses measuring 8 or 10 inches in thickiiess, and is sometimes associated 

 more or less closely with cyanite and rutile. Veatch* observed pyrophyllite 

 in the vein quartz breccia but states that it does not show evidence of 

 crushing and must therefore have been formed subsequent to the fracturing 

 of the quartzite. 



The exact relations of the pyrophyllite to the surrounding quartzite were 

 not conclusively established, since contacts were largely obscured, but 

 the field evidence suggests formation hy probable filling of a fracture or 

 other irregular spacing in the rock. This explanation finds confirmation 

 in a second occurrence of pyrophyllite recently noted by Veatch in the same 

 county about seven and one-half miles east of Lincolnton on the Peters- 

 burg road. Mr. Veatch informs us that both the mineral and enclosing 

 rock are very similar in texture and appearance to those at Graves Moun- 

 tain to the west, and that the pj'-rophyllite fills fractured quartz veins in 

 the quartzite. Although careful search was made no rutile was found in 

 the veins at this locality. 



In thin sections the microscope resolves the pyrophyllite aggregate 

 into a series of extremely minute fibers which are mostly radiate in arrange- 

 ment, sometimes parallel, with all intermediate relations observed. The 

 mineral is colorless in thin section, has strong birefringence, and contains 

 some small inclusions of rutile and magnetite or ilmenite. Yellowish- 

 brown iron oxide has filtered in along and between the boundaries of the 

 fibers in places, causing discoloration. 



An analysis of the pjTophyllite from this locality (column I), compared 

 with one of the same mineral from the Chesterfield district. South Carolina, 

 (column II), is given below. 



Personal communication, January, 1912. 



