MINERALOGIC NOTES ON PUCHERITE, PYRITE, 
TRICHALCITE, AND WAVELLITE. 
By Haru V. SHANNON, 
Assistant Curator of Geology, United States National Museum. 
INTRODUCTION. 
Minor investigations are constantly being conducted in this lab- 
oratory for the necessary purpose of accurately ascertaining the 
mineralogic identity of materials. These may be. specimens sub- 
mitted for identification by correspondents, they may be new and 
unlabeled material to be placed upon exhibition or filed with the 
reference collections, or they may be specimens already incorporated 
in the collections whose labeling is found to require confirmation 
or correction. These investigations may be conducted by chemical, 
optical, or crystaliographic methods or a combination of these as 
the case may require. Almost invariably new facts of importance are 
developed by these studies, and it is desirable that the results 
be published, firstly in order to permanently record the evidence 
upon which the specimen is labeled and secondly because the new 
data furnished in regard to the properties or occurrence of rare and 
unusual minerals are of interest and value to mineralogical science 
in general. 
It is a practice previously inaugurated in this department to com- 
bine several of these minor researches, even when they are not 
directly related to each other, into a paper of convenient length for 
publication in the Museum Proceedings. In the present contribution 
there are assembled short papers on four different subjects: Pyrite 
crystals of unusual crystallographic development from Arkansas, 
Pucherite from a new locality in Brazil in measurable crystals agree- 
ing with those previously recorded on European material and show- 
ing one new form, Trichalcite from a new locality in Idaho having 
optical properties agreeing with those of the mineral from the original 
locality and showing measurable crystals which add new information 
regarding the crystallography of this rare arsenate, and Crystallo- 
graphic and optical properties of wavellite crystals of two specimens 
from Montgomery County, Ark. 
No. 2455.—PROCEEDINGS U. S. NATIONAL Museum, VOL. 62, ART. 9. 
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