The Analysis of Feldspar*

ASSTRACT The methods commonly used for the chemical analysis of feldspar require an excessive amount of time, particularly if the analysis is to be used only for grading the material and where great accuracy is not essential. More rapid methods are described for determining alumina, calcium oxide, and the alkalis. In these, alumina is determined by precipitating with 8‐hydroxyquinoline in acid solution and then titrating an acid solution of the precipitate. Calcium oxide is determined by precipitating with oxalic acid without prior removal of aluminum and then titrating with standardized potassium permanganate. The alkalis are weighed as chlorides and potassium is determined by difference after sodium has been weighed as the triple acetate. Optional methods for attacking feldspar by acid instead of by fusion are described.