High-throughput 16S rRNA gene sequencing revealed that minerals significantly altered the community composition, promoting higher alpha diversity (Shannon and Chao1 indices) compared to the control group. Notably, minerals enriched diverse rare amplicon sequence variants (ASVs) in a highly treatment-specific manner, whereas abundant taxa remained largely consistent across treatments. Venn analyses showed that Olivine and Quartz promoted the most rare taxa, and these rare members contributed substantially to the overall community diversity.

At the phylum level,  mineral-treated groups showing increased Firmicutes abundance. At the genus level, mineral amendments enriched a variety of function-specific taxa, such as Klebsiella, Lysinibacillus, Tissierella, and Clostridium, across different soil sources. These enriched genera are known for nitrogen fixation, metal resistance, sulfate reduction, and decomposition of complex organics, highlighting mineral-driven selection for ecologically functional microbes. Despite spatial heterogeneity, the consistent enrichment of these taxa across samples underscores mineral's potential role in guiding microbial succession trajectories.

Our findings suggest that minerals not only restructure microbial community composition but also enhance functional diversity by selectively promoting rare, ecologically relevant taxa. This mineral-mediated community shift provides important insights into the mechanisms underlying microbial succession and has implications for soil ecosystem development and restoration.