There are a lot of new items in the new 2.4 update, especially with the Enkanomiya region. One of the items you get in the update is the Radiant Spincrystal. What is it exactly and how do you use it in-game?
How to use Radiant Spincrystal — Genshin Impact
So what is a Radiant Spincrystal and how do you get it? A Radiant Spincrystal is an item that you can purchase with the traveling merchant in your Serenitea Pot. The traveling merchant is a limited-time shop that brings goods like furniture and animals for your Serenitea Pot.
You can purchase 1 Radiant Sprincrystal 31 and 1 Radiant Spincrystal 41 for 100 Realm currency each.
Next, go to Tubby and select Realm Depot. Purchase Euphonium Unbound Soaring or Winding in the Riches of the Realm tab. Place this item anywhere in your teapot and when you interact with it, you can change the music of the Serenitea pot.
If you take a look at the Liyue tab, you will see locked music options. Use your Radiant Spincrystal to unlock those music options and use them in your Serenitea pot.
And there you have it, the Radiant Spincrystal is a requirement for unlocking Serenitea pot music!