The rarity of Sunken Frostshard is Rare. At this moment the item is available for trade.
Sunken Frostshard is a skin for Tidehunter. The skin was added to the game on November 29, 2017, it was created by CiDDi.
Sunken Frostshard is currently one of the most popular skins, but it is rarely seen in the game due to its high price.