271 Hillebrand and Schaller — Mercury Minerals, etc. 



Native Mercury. 



Native mercury occurs abundantly on nearly all of the speci- 

 mens, except those of kleinite, on which we have not seen it. 

 It is usually present as globular irregular masses associated di- 

 rectly with the other minerals. Globules often project from 

 small cavities on the surfaces of crystals of terlinguaite, egles- 

 tonite and montroydite, and are sometimes to be seen in the in- 

 terior of crystals of terlinguaite and montroydite, notably the 

 latter. While much of it is in the form of a fairly pure liquid, 

 a good deal is mixed with powdery oxychlorides as a sort of 

 stiff paste having a gray or greenish color and irregularly associ- 

 ated with the plainly crystallized oxychlorides and montroydite. 

 The proximate determination of this gray or greenish mass is 

 almost impossible. Some of the mass has a yellowish, almost 

 metallic sheen, which is perhaps largely an iridescent effect. 



Summary. 



Kleinite, as announced in 1905, belongs to the so-called mer- 

 cury-ammonium compounds, but no probable formula can be 

 deduced from the analyses. It may be a mixture of a mercury- 

 ammonium chloride in great preponderance, NHg 2 Cl.^H„0, 

 with an oxychloride and sulphate or oxysulphate of mercury. 



Terlinguaite is a mercuric-mereurous oxychloride, HgO.HgCl, 

 the formula of Moses being confirmed and the mixed nature 

 ascertained by tests. 



Eglestonite is a mercurous oxychloride, Hg„0.2HgCl, the 

 first authentic instance of such a compound, either artificial 

 or native, and not ng 6 C] 3 0. 2 as believed by Moses. 



Montroydite is mercuric oxide, as supposed by Moses and 

 proven now by direct determination of its oxygen content. 



Laboratory IT. S. Geological Survey, Washington, D. C, July. 



