When a creature uses an Aetherite Crystal, they restore spell slots as follows:

• 1st level spell slot:  Tiny
• 2nd level spell slot: Tiny
• 3rd level spell slot: Small
• 4th level spell slot: Small
• 5th level spell slot: Medium

To use an Aetherite Crystal, the creature must hold it against their skin and concentrate for 1 minute, during which time the crystal disintegrates. After using an Aetherite Crystal, the creature feels a sense of relaxation and calm.

Note: Aetherite Crystals are rare and highly valued, so they can be difficult to obtain. The DM may also rule that they have side effects or consequences for excessive use or misuse.