| Text | This crackling crystal contains the essence of an elemental plane. As an action, you can attach the shard to a Tiny object (such as a weapon or a piece of jewelry) or detach it. It falls off if your attunement to it ends. You can use the shard as a spellcasting focus while you hold or wear it.
Roll a d4 and consult the Elemental Essence Shards table to determine the shard's essence and property. When you use a Metamagic option on a spell while you are holding or wearing the shard, you can use that property.
Elemental Essence Shards:
d4 | Element | Shard
1 | Air | Elemental Essence Shard (Air)
2 | Earth | Elemental Essence Shard (Earth)
3 | Fire | Elemental Essence Shard (Fire)
4 | Water | Elemental Essence Shard (Water)
Source: Tasha's Cauldron of Everything p. 127 |