ei.lsworth-poithvin] CAMSELLITE 5 



Deducting the dolomite and chrysotile from the borate mixture 

 and recalculating we obtain the results given in lA. 



The formula indicated for the mineral is, therefore, 2MgO BoO,; . 

 H2O with ferrous and ferric oxide, manganous oxide and alumina in 

 small amounts apparently leplacing MgO. It is comparable to 

 Sussexite, which has the same general formula, but in which mangan- 

 ous oxide is much in excess of magnesia. 



Sussexite (Penfield, Am. Jour. Sci., 36, 323, 1888.) 



MnO 38.08 



MgO 15.92 



ZnO 3.24 



B.O, 33.31 



HoO 9.43 



99.98 



The water present Is certainly chemically combined since only 

 relatively small amounts are lost below a red heat. A one gram 

 sample was heated in a platinum crucible at various temperatures 

 w^Ith results as indicated below: 



Time Temperature 



3 days 110°C.. . . 



3 " 140 



2 " 180°±10°. 



6 hours 300 " . 



6 " 350 " . 



6 " .. .400 " . 



6 " 450 " . 



9 " 500 " . 



9 " 550 " . 



Total loss up to 550° 2.95 



Total water 10.40 



It thus appears to be a mineral of sufficient stability to admit 

 of its having been produced at the range of temperature commonh' 

 ascribed to pneumatolytic action. 



