The pore size range of the millimeter-scale porous mineral materials is greater than 0.1 mm, further divided into three subcategories: millimeter-scale small pores (pore size 0.1–1 mm), millimeter-scale medium pores (pore size 1–5 mm), and millimeter-scale large pores (pore size > 5 mm). The characteristics of their pore structures can be observed using an optical microscope and the naked eye. The main varieties include natural pumice, shale ceramsite, and clay ceramsite. Due to differences in formation and preparation conditions, there are significant variations in their pore-structure characteristics (Table 1).