A fundamental understanding of the factors influencing particle shape is of central importance for optimisation of the output quality from crushing plants for aggregate production. The literature reports that the wear on and setting of a cone crusher influence particle shape, The fact that wear on and the setting of a cone crusher influence particle shape is considered common knowledge and is also reported in the literature. To date, no mathematical model for predicting particle shape has been presented. A novel model capable of predicting aggregate shape is presented in this paper. The particle flakiness model has two parameters: the average particle size of the feed and the closed side setting (CSS) of the crusher. A common method used for controlling the process flow in a crushing plant is also demonstrated. Detailed process knowledge is important in order to minimize the circulating load whilst still maximizing product quality. The model shows that the flakiness of the product can be estimated with knowledge of the following two parameters: CSS and the average particle size of the feed. Additional investigations are needed to improve the precision of the model.