The Black Crown (Tibetan: ཞྭ་ནག་, Wylie: zhwa nag) is an important symbol of the Karmapa, the Lama who heads the Karma Kagyu school of Tibetan Buddhism. The crown signifies his power to benefit all sentient beings. Similar crowns in red are worn by the Shamarpa and the Tai Situpa, while Goshir Gyaltsab wears an orange crown. These crowns were bestowed by the Karmapa.
Legend tells that in a previous eon, in a former life as an accomplished yogi, the Karmapa attained the eighth level or bhumi of the bodhisattvas. At this time, 100,000 dakinis (female buddhas) manifested their hair as a crown, and offered it to the Karmapa as a symbol of his accomplishment.
Dusum Khyenpa, the 1st Karmapa, was regarded as an emanation of that yogi and his appearance was predicted by the historical Buddha Shakyamuni in the Samadhiraja Sutra:
A bodhisattva with the lion's roar will appear. He will use the power he achieved in deep meditation to benefit countless beings. By seeing, hearing, touching or thinking of him, they will be led to happiness