Natural particles, such as sand and dust, often have irregular, angular shapes without porosity. Such sedimentary particles can have a significantly different drag coefficients than spherical particles, and a robust drag coefficient model is needed to accurately predict their trajectory in multiphase flows. Such a model requires quantitative characterization of their shape. Herein it is shown that the Corey Shape Factor is a suitable parameter to characterize particle drag coefficient for a wide variety of particles with Reynolds numbers up to 2 x 10(5). This is accomplished by investigating the shape effects for both the Stokes drag regime and for the Newton drag regime to provide a comprehensive and validated drag model for irregular angular particles as a function of Corey Shape Factor. In addition, the shape of ISO 12103 Arizona Road Dust is measured (for the first time) to allow use of the corresponding drag model. (c) 2020 Elsevier B.V. All rights reserved.