MINERALOGICAL NOTES — ANDBRSON. 



125 



Four crystals were measured ; tliey are about 5 x "2 x -2 cm. 

 and colourless and transparent as ii;las3. Twelve forms were 

 identified, the indices and angles being tabulated below. 



The crystals have the following combinations (iii is figured). 



The largest faces are usually those of ni{l 10) and ^ (111); some 

 of the prism faces are slightly striated vertically ; n is striated 

 parallel to its intersection with b. The form 313, of which two 

 faces giving good signals were observed, has been previously re- 

 corded by Artini^ on the gypsum of Ballabio. 



^Aitini — Reud. K. Inst. Loinb. 

 App., Syst. Min., 1909, p. 48.) 



xxxvi., 1903, p. 1181 (fidt Dana— 2nd 



