Fusibility assessment of fluxing materials after burning at temperatures above 1200oC. The test is carried out using cones of standardized dimensions, conformed to the samples received. After burning at defined temperatures, the cones are evaluated for color, brightness and change in original shape, which is indirectly related to the viscosity of the liquid phases formed during burning. This is an analysis used to evaluate the fusibility and color of minerals such as feldspars, nephelines, basalts and granites, among others.