238 Uanksite, a new Anhydrous Sulphato- Carbonate. 



X. — On Hanksite. a new Anhydrous Sulphato r Carbonate, from 

 San Bernardino County. California. 



BY WM. EARL HIDDEX. 



Read May 25th, 1885 ; 



In the very complete and attractive exhibit of California min- 

 erals brought -to the World's Industrial and Cotton Centennial 

 Exposition at New Orleans, by Prof. Henry G. Hanks, State 

 Mineralogist of California, were several species of unusual in- 

 terest. 



Among these, was the new borate, Colemanite, with its large 

 and lustrous crystals so much resembling the finest of the Ber- 

 gen Hill datolites ; the new vanadium mica, Roscoelite, mixed 

 as it is mechanically with much native gold between its folia : 

 borax crystals, clear and bright, of unusual size ; stibnite in su- 

 perb crystals almost equalling the late discoveries in this species 

 in Japan, and many others equally noteworthy, and to which I 

 may refer in a separate paper later. 



Of particular interest to the writer was a small lot of appa- 

 rently hexagonal crystals to which had been given the name of 

 " Thenardite." Now as Thenardite is asserted in the text books 

 to be orthorhombic, I was prompted to measure the angles of these 

 crystals. Their seeming non-conformity in shape pointed to 

 the possibility of their being new — in angle, or type of form, 

 especially. The results confirmed my first suspicions of their 

 true hexagonal character, though my measurements were only 

 approximate, being made with a hand goniometer. 



Since the hexagonal character of the mineral, which seemed so 

 evident, might possibly be due to complex twinning of ortho- 

 rhombic individuals, it seemed advisable to have this question 

 decided on the basis of an optical examination ; and for this pur- 

 pose three of the best crystals were kindly given by Prof. Hanks, 

 and sent by me to Dr. Edward S. Dana for that exact crystallo- 

 graphic definition needed in this case, and which he always so 



