Buy OSRS Crystal key
The OSRS Crystal key is a members item that opens the crystal chest inside a house in Taverley. Each key works one time. Once you use it on the chest, the key is gone. Every opening gives an uncut dragonstone plus other items. Top rewards include 3 runite bars, rune platelegs or a rune plateskirt, and another half of the crystal key.
The key is made by joining a tooth half of key with a loop half of key. Key halves come from Barrows, Treasure Trails, Managing Miscellania, the rare drop table and more. Full keys also drop from bosses like Kree'arra, the Kraken, Sarachnis, the Alchemical Hydra and the Grotesque Guardians.
A crystal key can also be upgraded at a singing bowl in Prifddinas. Add 10 crystal shards to make an enhanced crystal key. This needs level 80 Smithing and Crafting and gives 500 XP in both skills. The enhanced key opens the Elven Crystal Chest in the Tower of Voices, which gives better rewards.
The crystal key is also needed for a medium Falador Diary task.