The shape of atmospheric mineral particles of 0.1--6 &mgr;m radius was studied by electron microscopy applied to the samples collected in three arid regions in China (Qira in the Taklamakan Desert, Zhangye near the southern border of the Badain-Jaran Desert and Hohhot in northern China). In all three regions, the mineral particles showed irregular shapes with a median aspect ratio b/a (ratio of the longest dimension b to the orthogonal width a) of 1.4. Although the aspect ratio exhibited no clear size dependence, the circularity factor (4&pgr;S/l2; S is surface area and l is periphery length) tended to decrease with increasing radius, suggesting the presence of aggregated mineral particles at larger sizes. The ratio of particle height-to-width h/a was also evaluated by measuring the shadow length. The median ratio h/a was 0.49 in Hohhot, 0.29 in Zhangye and 0.23 in Qira. Analytical functions were fitted to the grand total of the frequency distributions of aspect ratios, height-to-width ratios and circularity factors allowing parametric calculations of radiative effects and calculations of optical and sedimentation behavior of mineral particles. ¿ 2001 American Geophysical Union