The rarity of Golden Nirvana is Rare, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Golden Nirvana is a skin for Phoenix. The skin was added to the game on January 11, 2017, it was created by Keanhotshine.
Golden Nirvana is currently one of the most popular skins, but it is rarely seen in the game due to its high price.