A calcined or ignited sample (0.9 g) is added to 9.0g of Lithium Borate Flux (50% - 50% Li2 B4 O7 - LiBO2), mixed well and fused in an auto fluxer between 1050 - 1100 degrees Celsius. A flat molten glass disc is prepared from the resulting melt. This disc is then analyzed by X-ray fluorescence spectrometry.