i873-] 



Mineralogy. 135 



doubly-refracting mineral. In many of its properties it is closely allied to the 

 rare British mineral, leadhillite, from which it differs, however, in density, in 

 the presence of water, and in certain other characteristics. 



A new ore of mercury from Guadalcazar, in Mexico, has been described by 

 Dr. T. Petersen, under the name of Guadalcazarite. It is a compact or crypto- 

 crystalline iron-black mineral, with a metallic lustre and a black streak. The 

 specific gravity is 7"i5. An analysis yielded — Sulphur, 14*58 ; selenium, 1/08 ; 

 mercury, 7973 ; zinc, 4*23 ; with traces of cadmium and iron. Guadalcazarite 

 is, therefore, a double sulphide of mercury and zinc, corresponding to the 

 formula 6HgS + ZnS, but with part of the sulphur replaced by selenium, and 

 perhaps a small proportion of the zinc by cadmium. 



In a recent number of the " Annales des Mines," M. Bertrand describes a 

 curious yellow or reddish substance from the province of Los Bordos, in Chile, 

 and found to contain the chlorides of silver and mercury, with oxide of mer- 

 cury. It is believed that this substance is a mixture of two mineral species. 

 One of these is a double chloride of silver and mercury, containing AgCl 40*69, 

 and Hg 2 Cl 59-31 percent: this new species is called Bordosite. The other 

 constituent is ordinary protoxide of mercury, which in this native form is to 

 be termed Hydrargyrite. 



Under the name of Syngenite, Zepharovich has lately described a new 

 mineral from Kalusz in Galicia. It occurs in the form of colourless tabular 

 crystals, much resembling those of gypsum, and associated with crystals of 

 sylvine, or chloride of potassium, in the salt mines of Kalusz. Syngenite is a 

 hydrous double sulphate of calcium and potassium, somewhat resembling 

 polyhalite, from which it differs in that it contains scarcely any sulphate of 

 magnesium. The native crystals are almost identical with those of the 

 similar product formed in the laboratory ; but though belonging to the rhombic 

 system, they affect a curiously deceptive monoclinic habit. 



Herr H. Griineberg has communicated to the German Chemical Society a 

 memoir on the properties and economic applications of the mineral Kieserite. 

 This is a hydrous sulphate of magnesium, containing only a single molecule 

 of water, and hence differing from ordinary crystallised Epsom salts. 

 Kieserite occurs abundantly among the " abraum salts," or deposits of mag- 

 nesium and potassium salts in the upper beds of the salt mines at Stassfurt, 

 near Magdeburg. It is extensively used in Manchester for dressing cotton 

 and other fabrics, and it is also valued as a manure. Kieserite and common 

 salt, reacting at a low temperature, furnish sulphate of sodium — hence another 

 application of the mineral. Griineberg has succeeded in preparing a double 

 sulphate of magnesium and calcium by igniting a mixture of kieserite and 

 gypsum, and has introduced this double salt as a hard and durable artificial 

 stone. 



At Nohl, near Kongelf in Sweden, Professor Nordenskjold has discovered a 

 new mineral which he terms Nohlite. This is a hydrated niobate of yttrium, 

 uranium, zirconium, calcium, iron, &c. The mineral resembles the Uralian 

 Samarskite, but contains more than 4-5 per cent of water. 



Some few years ago, Mr. Ulrich, in his excellent notes on the mineralogy 

 of Victoria, described some beautiful crystals of Herschelite from Chambers's 

 basalt quarries at Richmond, near Melbourne. Samples of these crystals 

 have lately been analysed by Herr Kerl in the laboratory of the University of 

 Gottingen with the following results : — Silica, 43*7 ; alumina, 21*8 ; lime, 8*5 ; 

 soda, 3*5 ; potash, traces ; water, 22*2. Compared with the typical herschelite 

 of Sicily, the Australian mineral contains much less silica, a larger proportion 

 of water, and a notable difference in the proportion of lime and alkalies. 

 Indeed a specimen of Sicilian herschelite contained only 0*31 per cent of 

 lime, but as much as 8*84 of soda and 4-28 of potash. These differences in 

 chemical composition have been considered sufficient to justify the separation 

 of the Australian mineral from the species herschelite, in spite of the close 

 agreement in the crystallographic characters of the two substances. Herr 



