A cosmetic substance, likely antimony sulfide (kohl), used for eye makeup—darkening and defining the eyes. Second Kings 9:30 describes Jezebel 'painting her eyes' before her fateful encounter with Jehu, suggesting beautification or defiance. First Chronicles 29:2 mentions it among precious materials David gathered for the temple—possibly for decorative inlay work. Isaiah 54:11 uses it in God's promise to restore Jerusalem: 'I will lay your foundations with antimony'—perhaps referring to dark, precious stones set in mortar. Jeremiah 4:30 denounces beautifying eyes with paint while facing destruction—cosmetics can't save from judgment. The term represents both cosmetic enhancement and valuable dark mineral.