The soil small-strain shear modulus, G₀, is necessary for static and dynamic analyses of soils and is often correlated to other soil properties such as density and void ratio, on their turn depending on grain size distribution. In some cases of dynamic loading, change in grain size distribution (GSD) of soils, especially for calcareous sands might occur. In addition, many of these sand types behave differently from silica sands due to their mineralogy and particle characterization. In this paper, a concise literature review of parameters influencing G₀ is given in detail. The findings prove that particle shape is a main factor affecting G₀. Less dynamic stiffness is found for particles owning less angularity and more sphericity. The results also show that calcareous sand gives higher values of G₀ than silica sand. Especially, the normalized shear modulus (G₀/e^-B) has a good correlation with the uniformity coefficient (C_u). The increases in C_u and finer particles have a negative influence on G₀. Moreover, a comparison is given between the values of G₀ predicted by this study and by previous studies.