﻿354: F. W. Clarke— Lithia Micas. 



The color of the latter is very rich and the appearance of the 

 material carrying the associated minerals is strikingly charac- 

 teristic. It resembles nothing from the other localities of the 

 region. Green tourmaline occurs here but sparing^, while 

 the spodumene is enormously developed, showing faces over 

 a metre in length. At the other lepidolite localities spodu- 

 mene is one of the scarcer minerals. 



Paris. — The famous locality known as Mt. Mica has been so 

 thoroughly studied by mineralogists that no detailed account 

 of it is needed here. The lepidolite occurs both in the ordi- 

 nary, purple, granular form and in broad foliations resembling 

 muscovite. Analyses of it have been published by Berwerth 

 and by Rammelsberg,* which agree fairly well with the results 

 obtained in this laboratory. 



Hebron. — The deposit at this point, about seven miles southeast 

 of Mt. Mica, has long been well known to collectors. It has only 

 been superficially opened, however, and deserves more system- 

 atic exploration. The lepidolite, which is coarsely granular and 

 purple, is especially interesting on account of its yield in cassia 

 and rubidia, which, after their identification by Johnson and 

 Allen here, were also found in the lepidolite of Rozena. As 

 yet no complete analysis of the Hebron mineral seems to have 

 been published. For the specimens examined in this labora- 

 tory I am indebted to the kindness of Professor Gr. J. Brush. 



Associated with the Hebron lepidolite there have been 

 found many specimens of red and green tourmaline, which, 

 while preserving their crystalline form, have undergone an 

 alteration into a softer mineral of an opaque, talcose appear- 

 ance. Some of the material so derived from tourmaline has 

 been supposed to be lepidolite ; and as it was possible that a 

 study of it might have interest, an analysis was made by Mr. 

 R. B, Riggs. The specimen chosen was originally rubellite, 

 and its specific gravity, as determined by Mr. T. M. Chatard, 

 was 2°87. Analysis as follows : 



Si0 2 43-90 



A1 2 3 38-71 



Fe 2 3 -58 



FeO -25 



MnO -04 



CaO ,. .41 



MgO -05 



Na 2 .-_. 1-05 



K 2 .10-92 



H 2 4-25 



F none 



B 2 O g _ _ _ trace 



100-16 



* See third supplement to Dana's Mineralogy, pp. *78, 79. 



