E Guan Shi

E Guan Shi (“goose-tube stone”) is a mineral substance, not a plant. It is a tubular, hollow stalactite of calcium carbonate (calcite/aragonite, CaCO₃) formed in limestone caves by slow precipitation from dripping mineral-rich water and prized in Chinese materia medica when it occurs as a narrow, quill-like, hollow soda-straw stalactite resembling a goose feather’s shaft. Specimens are white to pale grey or yellowish, with a chalky to translucent surface, fibrous radial structure on cross-section, and a thin axial canal. Larger, dense, branched stalactites with a clearly tubular interior are also accepted under this name in some regional sources. E Guan Shi is broken into pieces and water-levigated before use; in TCM it is regarded as warm and is used to warm the Lung and direct rebellious qi downward, to consolidate descent, and to treat cold-pattern phlegm-rheum and certain wheezing conditions. Verify mineralogical authenticity before clinical use.