This is an ancient polyhedral dark-purple agate bead (commonly known as a "Vajra bead" or faceted agate bead). It features a distinctive cuboctahedral shape with multiple hand-cut facets, measuring approximately 1.5 cm in diameter. Crafted from a deep, near-black agate that reveals a rich, translucent purplish-brown hue under strong light, its surface is covered with an authentic antique patina, fine manual polishing marks, and subtle micro-weathering indentations. The perforation is characteristic of ancient counter-drilling, showing a slightly uneven interior with step marks. It is dated to the Han Dynasty through the Wei, Jin, and Northern & Southern Dynasties period (approx. 2nd century BCE – 6th century CE),