W. E. Hidden — On HanJcsite. 135 



Crystals striated horizontally. They are commonly termin- 

 ated at both ends of the prism and are very symmetrical in 

 shape. They average, as thus far seen, about one centimeter 

 in length and thickness, with and /as predominating planes 



(fig- !)• 

 Sometimes the crystals are confusedly grouped (fig. 2), as 



from a common center, much like the aragonite from a noted 

 European locality. For some late years mineralogists have 

 received from several localities in the far West groups of 

 tabular crystals that were hexagonal in appearance, very 

 impure in composition, and to which the name of aragonite has 

 l. 2. 



been attached. For the most part they are simply calcium 

 carbonate mixed with sand and mud, and are without cleav- 

 age. It is very probable that they are pseudomorphs after the 

 sodium sulphato-carbonate here described. In particular I 

 refer to crystals which I have seen credited to Colorado and to 

 Nevada. 



The crystals here analysed were found with salt, thenardite, 

 tincal, etc., at the works of the San Bernardino Borax Co., in 

 San Bernardino County, California. 



The density of this new California mineral is 2*562. Its 

 hardness, 3'-3 - 5. It is readily soluble in water. Effervesces 

 with acids. It affords, when dissolved in water, an abundant 

 precipitate of barium sulphate when barium chloride is added 

 to the solution. On addition of silver nitrate to a fresh solu- 

 tion chloride of silver is precipitated, showing that chlorine is 

 also present. Gentle ignition develops no appreciable loss in 

 the weight of the mineral. 



The crystals are transparent to semi-opaque, with a white 

 waxy color inclining to yellow. Surfaces never highly pol- 

 ished nor very smooth. 



The definite formula deduced from Mr. Mackintosh's analysis, 

 taken together with the form, warrants me in announcing this 

 as a new mineral species. I therefore propose for it the name 

 of Hanksite, after Professor Henry G. Hanks, of California, to 

 whom we are so largely indebted for our knowledge of the 

 minerals of the Pacific coast. 



Newark, N. J., May 23, 1885. 



