Antimony (Sb) is a critical raw material essential for modern technologies, including energy storage, photovoltaics, and flame retardants, yet its primary supply is increasingly constrained. Secondary sources, particularly legacy mine wastes, represent an important but underexplored unconventional resource that may contribute to sustainable raw material supply while reducing environmental risk. North Macedonia hosts several former Sb-rich mining districts, where large volumes of mine waste remain exposed to ongoing weathering and element redistribution. This study investigates the resource potential of Sb in mine wastes from the Lojane Sb-As-Cr mine (Dordevic et al. 2019; Serafimovski et al. 2023) and the Allchar, Sb-As-Tl-Au polymetallic deposit (Vanek et al. 2024), with implications for future exploration at Krstov Dol, former Sb-mine. These sites contain substantial quantities of Sb hosted both in primary sulfides such as stibnite, as well as in secondary Sb-minerals (mostly Sb-oxides and mixed Fe- and Ca-Sb-oxides) formed during post-mining alteration. However, the nanoscale distribution, speciation, and stability of Sb within these materials remain poorly constrained, limiting reliable assessment of their recovery potential. To address this, a multi-scale mineralogical approach was applied, combining scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), Raman spectroscopy, nano-focused X-ray fluorescence (nano-XRF) and transmission electron microscopy (TEM). Nano-mineralogical analyses reveal that besides primary ore minerals Sb is also concentrated in secondary phases, including Sb-oxides, Sb-rich Fe-oxides, roméite-group minerals, and amorphous nanoparticulate assemblages. These nanoscale phases act as both sinks and potential sources of Sb, controlling its environmental mobility and influencing its technical recoverability. Furthermore, weathering processes promote localized Sb enrichment in fine-grained fractions, increasing the potential economic value of mine waste materials. The results demonstrate that mine wastes in North Macedonia represent significant unconventional Sb resources, where mineralogical controls at the nano-scale govern both environmental behavior and resource potential. These findings contribute to the development of resource-efficient strategies aligned with circular economy principles and highlight the importance of advanced mineralogical characterization for future exploration, including emerging targets such as Krstov Dol.