Source: Out of the Abyss

Wondrous item, rare (requires attunement)

Created by the stone giant librarians of Gravenhollow. this nineteen-inch-long shard of quartz grants you advantage on Intelligence (investigation) checks while it is on your person.

The crystal has 10 charges. While holding it, you can use an action to expend some of its charges to east one of the following spells from it: speak with animals (2 charges), speak with dead (4 charges), or speak with plants (3 charges).

When you cast a divination spell, you can use the crystal in place of one material component that would normally be consumed by the spell, at a cost of 1 charge per level of the spell. The crystal is not consumed when used in this way.

The crystal regains 1d6 + 4 expended charges daily at dawn. If you expend the crystal's last charge, roll a d20. On a 1, the crystal vanishes, lost forever.