The shape factor of quarry rock - defined by the ratio of the median nominal diameter and median sieve diameter - is often applied throughout various phases in the realization of a granular hydraulic structure. In this research, the value as well as the variability of the shape factor is reassessed. Also the dependency of the shape factor on elongation and blockiness - two parameters to describe the shape of rock - is examined. In order to do so a series of experiments has been performed on multiple rock samples. The research focuses on experimental rock data. Each file represents a specific rock grading. On each grading, sieve tests, density tests and shape tests have been performed in both IJmuiden, the Netherlands and Slovag, Norway.@en