Abstract: Clay minerals are the raw materials for making Zisha (purple clay) crafts. Currently, the conventional methods used in the industry to determine the quality of clay minerals primarily include major element analysis, mineral composition and plasticity, loss on ignition, shrinkage rate, and water absorption rate. Although these conventional tests effectively evaluate the quality of clay minerals, they struggle to distinguish between siltstone and argillaceous siltstone—two types of rocks that significantly affect clay mineral quality—based on their chemical composition. During the exploration of Yixing clay mineral resources, the author utilized the Tescan Integrated Mineral Analyzer (TIMA) to test, analyze, and compare the mineral composition, content, and particle size distribution of minerals in borehole core samples and local high-quality clay materials. The results showed that high-quality clay minerals account for over 30%, with a very narrow particle size distribution, primarily within the clay-sized fraction. In contrast, quartz exhibited a broader particle size distribution, ranging from clay-sized to fine sand-sized particles, with a relatively even distribution across different size fractions and a stable or coarser trend in quartz content. Therefore, the composition, content, and particle size distribution of the minerals present are critical factors affecting the quality of clay minerals. TIMA testing not only addresses the limitations of chemical composition in distinguishing between ore and non-ore materials but also effectively identifies the intrinsic relationship between ore quality and product quality.