Prof. B. Silllman on some American Minerals. 457 

 -'■■ II. On Unionite. '''" i!'- < 'f • 



'iro"> il. .<>'^mn'i 



The next mineral to be noticed is from the same specimen 

 which furnished me the euphyllite. In general appearance it 

 somewhat resembles scapolite or spodumene. It is implanted 

 in black tourmaline, and is intimately associated with the eu- 

 phyllite. Its form is discernible only by its cleavages, which 

 are distinct in one direction, the planes dividing the mineral 

 into parallel laminae ; in two other directions less distinct, but 

 yielding a form probably triclinate*. Lustre, vitreous. Co- 

 lour, yellowish-white to white. Hardness, 6 to 6'5. Gravity, 

 3*2984. Brittle, and easily reduced to powder. In acids 

 does not gelatinize. 



B. B. in forceps, it whitens, swells up and fuses to a white 

 enamel, giving out at the same time an extremely brilliant 

 light. In the matrass it gives out water which is acid, and 

 the glass is etched with hydrofluoric acid. Qualitative ana- 

 lysis detected silica, alumina, magnesia and soda. The 

 amount of water was determined by the loss on heating, and 

 the fluorine was not separately estimated. In the quantitative 

 analysis the mineral was attacked by carbonate of baryta. 



The following are the results of analysis. Taken, 0*7335 

 grm. Yielded — 



Oxygen. 

 Silica .... 0-32385=44'-l51p.c. 22-940 = 7 



Alumina . . . 0-31000 42-263 19-763 6 



Magnesia . . . 0*05400 7*361 2-85\ , 



Soda 0-01270 1-731 0-46J "^ "^^^ ^, 



Water and fluorine 0-02590 3*532 ,,^ ^.j^'UG 1 



Loss 0*00705 0-962 ■,!:!. 



' 0-73350 100-000 



7 atoms Silica. . . 4041-17 = 44-86 per cent. 



6 atoms Alumina . . 385400 42*78 



3 atoms Magnesia . 775*06 8*62 



3 atoms Water . . 33744 3*74 



9007-67 100*00 



3RO, 6Alt)3, 7Si03, 3HO=3RO, Si03 + 6(Art)3, SiCF) 

 -F3HO. 



This formula and constitution are believed to be unknown 

 in any previously noticed species among minerals, and I there- 

 fore propose it as new, and suggest for it the name Unionite, 

 derived from Unionville, its locality. At present it is a rare 

 substance, but I understand that .the place where it was found 



* The angles do not admit of nieasurement. 



