146 Graton and Schaller — JPUrpurite, a new Mineral. 



Art. XIX. — Purpurite, a new Mineral y* by L. C. Graton 

 and W. T. Schaller. 



Tfitroduction. 



In the central portion of the Carolinas there occurs a belt of 

 metamorphic rocks penetrated by narrow dikes of pegmatite, 

 many of which contain lithium minerals. There can be little 

 question but that the dikes of pegmatite represent the final 

 product of a parent magma which has crystallized as granite 

 and appears almost continuously along the extent of this belt. 



Attention was first directed to these pegmatites by the 

 discovery of cassiterite in them. In the autumn of 1904," one 

 of the writers made an examination of these tin deposits for 

 the U. S. Geological Survey. During the course of this study, 

 Mr. J. L. Daniels, superintendent of the Faires tin mine at 

 Kings Mountain, Gaston County, 1ST. C, called attention to a 

 purplish material encountered within a few feet of the surface 

 in the workings of that mine. Thanks are due to Mr. Daniels, 

 who kindly supplied much of the material obtained. Prelimi- 

 nary examination failed to identify the material with any 

 known mineral, although its properties seemed to be those of 

 a definite crystalline compound. Chemical analysis shows that 

 the material is a new mineral, being a hydrous manganic ferric 

 phosphate — the only manganic phosphate known. 



The most striking feature of this mineral is its purple or 

 dark reddish color, and for this reason it has been named 

 purpurite, from the Latin purpura, purple or dark red. 



Since the discovery of this mineral in North Carolina, the 

 same mineral has been noticed on some specimens from San 

 Diego County, California, These had been collected by one of 

 the writers, and through the courtesy of Mr. F. M. Sickler, of 

 Pala, several more specimens from this locality have been 

 obtained. They are from one of the lithium-bearing pegma- 

 tite dikes on Hiriart Hill, Pala, San Diego County. The 

 mineral occurs with triphylite, and possesses the same purple 

 color as the North Carolina specimens. Under the microscope, 

 the appearance and properties of the mineral from the two 

 localities are identical. There is, however, not enough of the 

 California material for chemical examination. 



Occurrence and Physical Properties ; by L. C. Graton. 



The mineral purpurite is found in small irregular masses in 

 the tin-bearing pegmatite dikes, and in the near-by schist at 

 the Faires mine. In most cases it occurs in narrow lenses or 

 * Published by permission of the Director of the U. S. Geological Survey. 



