In determined civil and mining projects there are no chances to conduct a geotechnical characterization on soils with oversize based on in situ and laboratory testing. In these cases it is required to use charts and correlations to predicting some important geotechnical parameters of these soils. Based on this, this article is focused in three topics. The first topic is the chart to estimate the minimum and maximum void index in granular materials. Some previous charts are shown and a new chart and data is included. The second topic discussed is an influence of the D₅₀ in the maximum void index. Laboratory testing results shows that larger D₅₀ decrease the maximum void index independently of the uniformity coefficient C_U. The last topic discussed is the peak friction angle based on the Leps' Chart. In this work, new large triaxial data is included into this chart and some recommendations to use it appropriately are proposed.