On the Occurrence of Glauberite at Borax Lake, California.
BY B. SILLIMAN.
Glauberite, a species not before recognised as occurring in North America occurs at Borax Lake, where it has lately been obtained in blue clay, brought up from a depth of forty feet by an artesian boring. No other crystallized, species was detected in the masses of clay examined.
Glauberite is a sulphate of lime and soda, half an atom of each base in combination with an atom of sulphuric acid. It is usually associated with rock salt, as at Villa Rubia, in New Castile, and also at Ausee, in Bavaria, and in the salt mines of Vic, in France. In the Atacama desert in Peru, it is associated with a fibrous borate of lime called Hagesine. Mr. Stretch, the State Mineralogist of Nevada, in his catalogue of minerals found in that State, mentions borate of lime (Hagesine) as occurring in globular masses and in layers from two to five inches thick, alternating with layers of salt in a salt marsh in the Columbus mining District, Esmeralda County. It is quite possible that a careful scrutiny would detect glauberite also in this association so analagous to that of Atacama.
Reference was also made to the occurrence of the species laghassite detected by Prof. S. in 1864, at the little Salt Lake near Rag Town in Nevada, as illustrating in an interesting manner, the chemistry of these bodies of saline water. The latter species is a hydrous, carbonate of lime and sodium, while glauberite is a sulphate of the same bases. Both salts undoubtedly result from the reaction of the respective elements pre-existing in solution in the saline waters.
The crystals of glauberite from Borax Lake occur in very thin flattened tables, derived apparently from the great extension of the faces O of the Monactinic prism.
Mr Bloomer read the following: