A. J. Moses — New Mercury Minerals from Texas. 259 



The name Terlinguaite, — This name should be limited to 

 the yellow monoclinic oxychloride of mercury here described 

 in order to remove the confusion at present existing. Mr. 

 W. H. Turner"^ first nsed the name terlinguaite in the follow- 

 ing words : " In addition to cinnabar, mercury occurs in the 

 native form and as a white coating and as yelloio-green crystals. 

 Prof. S. L. Pentield has identified the . . . greenish crystals as 

 an oxychloride of mercury forming a new mineral species for 

 which 1 have suggested the name terlinguaite." 



To the miners in the Terlingua district terlinguaite is " a 

 heavy softf cadmium yellow substance in masses or powder 

 with a distinct green shade. It blackens on" exposure and 

 gives by rough retort tests 60 to 70 per cent of mercury." 

 Some of this material has been recently sent to me and will be 

 examined ; the description, however, suggests a mixture of 

 eglestonite and terlinguaite. 



Prof. Penfield sent me by request the best two of the speci- 

 mens received from Mr. Turner and at the same time wrote 

 that *' I have never given these minerals more than superficial 

 examination and they may not be oxychlorides; I simply sug- 

 gested that they might be." One of these specimens received 

 from Prof. Penfield was undoubtedly the material here 

 described as terlinguaite, crystal 4 having been taken from 

 the specimen and the color change to olive-green on exposure 

 being very pronounced. The other specimen, although appar- 

 ently an oxychloride, was evidently the undetermined mineral 

 spoken of in JN'o. 5 of this article. 



Of the three possibly different substances to which the 

 name terlinguaite has hitherto been applied we have therefore 



1st. The mineral here described. 



2d. The undetermined rough yellow crystals mentioned in 

 No.' 5. 



3d. The pulverulent yellow masses. 



It is therefore proposed that the name terlinguaite be defin- 

 itely limited to the mineral here described. 



3. Montroydite, Mercuric Oxide in Orthorhomhic Crystals. 



Associated sparingly with the eglestonite and terlinguaite 

 and in one or two instances occurring as masses of an inch or 

 more on a side there was found a third new mineral. The 

 most frequent occurrence was as a velvety incrustation of 

 orange-red needles projecting from the surface of little hollow 

 spheres and hollow pipe-like stems. The supporting material 

 forming the sphere or pipe was metallic in luster, white to 



*The Terlingua Quicksilver Mining District, Brewster Co., Texas, bv W. 

 H. Turner, Mining and Scientific Press, San Francisco, July 21, 1900. 

 f From a letter by W. P. Jenney. 



