BestAmulets Amulet Mayan Unity of All Things Hunab Ku Black Agate Pendant Necklace Best Amulets Collection. Amulet Mayan Unity of All Things Hunab Ku Protection Powers Black Agate Medallion Circle Pendant NecklaceAmulet Mayan Unity of All Things Hunab Ku Black Agate Pendant Necklace Natural Grade A+ Black Agate Gemstone. Amulet Medallion SIZE: 35mm (1  inches in diameter) and 8mm Thick. All Art Work is Engraved on top of the Gemstone. Metallic Color Ink is used on Black Agate Medallions. Ready to wear with Cotton Waxed Cord which Adjusts from 15 up to 24 inches long and you may wear it any length you desire