Determination of sample refractoriness. Analyses are carried out in comparison with reference pyrometric cones, which indicate the samples’ ability to withstand high temperatures without deforming or melting. The tests are carried out up to the limit temperature of 1600oC, in laboratory muffle furnaces. The results are useful for evaluating the potential of raw materials for application in the refractory sector and also allow the evaluation of the performance of products (refractory or not) when subjected to heat.