OX SAND-BARITES FROM KIIARGA, EGYPT. 



By Joseph E. Pogue, 



Assistant Curator, Division of Mineralogy, U.S. Nairn, ml Museum. 



Introduction. — Calcite, gypsum, and barite are distinguished, 

 above all other minerals, by the large quantities of sand which they 

 can inclose upon crystallization, without being materially hindered 

 in the development of crystal outline. As examples of the first, 

 there come to mind the well-known sand-calcites of Fontainebleau, 

 France, containing 50 to 60 per cent sand, which have been described 

 by Lassone ° and Ilaiiy; h and the siliceous calcites from the Bad 

 Lands of South Dakota, with 60 to 63 per cent of rounded quartz 

 grains, accounts of which have been given by Penfield and Ford ' 

 and by Barbour. d Examples of the second are not so familiar, 

 but gypsum including fine sand is found in Sussex, New Brunswick/ 

 Carcote, Bolivia/ and'some other localities. Sand-barites are also 

 uncommon. It is the purpose of this paper to recount the localities 

 where these, as well as baritic sandstones, occur; and to describe, 

 from a new locality/ an unusually full suite of crystals and groups 

 acquired in November, 1909, by the U. S. National Museum (Cat. 

 X.». 86580). 



Historical. — The first mention of arenaceous barites appears to be 

 in 1853, when Reuss* called attention to thin tabular crystals inclos- 

 ing much sand, which had been discovered at Tetschen, near Treb- 

 nitZj Bohemia. 



" Mem. Acad. Roy. Paris, 1775, p. 65. 



& Trails de Mineralogie, vol. 1, 1822, p. 121. 



cAmer. Journ. Sci., vol. !), L900, pp. 352 354. 



<*Bull.Geol. Soc. Ajmer., vol. 12, L901, p]>. L65-178. Also Barbour and Fisher, 

 Amer. Journ. Sci., vol. It. L902, pp. 451^154. 



«Arner. Journ. Sci., vol. 35, L863, p. 2115. 



/Verh. Vereirj Santiago, Chile, vol. 2, L892, p. 238. 



v M. J. Couyal ( La celestite et la barytite d'Egypte. Bull. Soc. Min. Frame, 

 vol :n, 1908, p. 298) devotes a half page to a brief account of clear crystals of barite 

 from Kharga, showing the following forms* (001), (110), (011), (010), (130), (210), 

 (102 i, (III). These, however, do no) contain sand. 



''A. E. Reuss, [Note], Lotos, Zeitschr. fur Naturw., Prague, vol. 3, L853, p. 72. 



Proceedings U. S. National Museum, Vol. 38, No. 1726. 

 Proc.N.M.vol.38— 10 2 17 



