Hillebrand and Schcdler — Mercury Minerals, etc. 259 



Art. XX VI. — The Mercury Minerals from Terlingua, Texas; 

 Kleinite, Terlinguaite, Eglestonite, Montr oydite, Calomel, 

 Mercury ;* by W. F. Hillebrand and W. T. Schaller. 



In the late fall of 1905 the senior author received for identifi- 

 cation from Mr. H. W. Turner, at that time connected with 

 one of the mining companies of Terlingua, Texas, specimens of 

 two minerals from the well-known Terlingua mercury field in 

 Brewster County. One of these proved to be the unidentified 

 mineral referred to as No. 5 by Professor A. J. Moses in his 

 paperf on new mercury minerals from that district, namely 

 terlinguaite, eglestonite and montroydite, the last of these 

 being mercuric oxide, the others oxychlorides. Preliminary 

 tests having shown that .No. 5 belonged to the so-called mer- 

 cury-ammonium compounds, hitherto unknown in nature, a 

 brief announcement^: of this fact was made in order to secure the 

 field for as full an investigation of this unique mineral and 

 its associates as the material on hand and to be obtained might 

 permit. 



This work has been conducted at intervals during the past 

 18 months and is yet incomplete with reference to the new 

 mineral. It has, however, extended over so \ong a time and 

 the chances for obtaining more perfect material than that 

 already available are so slight, that it is deemed inadvisable to 

 longer delay publication of the results obtained. The full 

 details of the work herein summarized will be found in a bul- 

 letin of the U. S. Geological Survey, the appearance of which 

 will unfortunately be delayed still longer, chiefly on account of 

 the plates that are to illustrate it and the unavoidable delays 

 attending publication. Although the present condensation 

 reproduces the essential points as to the chemistry of the min- 

 erals, it but touches their crystallographical side, which, 

 though of much interest for the great number of forms shown 

 by most of the minerals, requires too extended treatment for 

 a resume of this character. Further, many observations of 

 interest that can not be detailed here were made upon which 

 some of the conclusions were based, particularly in studying 

 kleinite, the mercury-ammonium compound. For these, as well 

 as the details of crystallography and association, reference must 

 be made to the full report. 



A few words, however, with reference to their association 

 as observed by us are necessary in this place. The minerals 



* Condensed from a forthcoming bulletin of the U. S. Geological Survey, 

 chemistry bv Hillebrand, crystallography, etc., by Schaller. 



fThis Journal [4], xvi, 253 (1903). 



% Science, xxii, 844 (1905); J. Am., Chem. Soc, xxviii, 122(1906); this 

 Journal [4], xxi, 85 (1906). 



