Natural single crystals of hemo-ilmenite with y≈0.83 are described as solid solution.  The single crystals have R3¯ structure, which is homogeneous with respect to transmission electron microscopy resolution. Inhomogeneity on a molecular level is documented by ESR spectroscopy, which reveals the generation of Ti^(IV)-enriched Fe^(III) clusters at T⩽20 K. The ZFC–FC magnetization curves and ac susceptibility measurements indicate inhomogeneity in the magnetic structure of the solid solution at low temperature, which is manifested by spin glass-like properties at about 40 K. These findings provide evidence that chemical heterogeneity on a molecular level and subsequent magnetic disorder enhance the dynamics of the magnetization, i.e. the magnetic metastability in natural hemo-ilmenite solid solution.