春秋戰國時代墨玉扳指 The black jade thumb ring is of cylindrical form, the jade is of black, green, and brown color tone, with mottled interior and slight russet. The black jade thumb ring is of cylindrical form, the jade is of black, green, and brown color tone, with mottled interior and slight russet. Inner Diameter: 1 in (2.5 cm)