Gem of Seeing
Wondrous Item, rare, requires attunement · 2024 rules, SRD 5.2
This gem has 3 charges. As a Magic action, you can expend 1 charge. For the next 10 minutes, you have Truesight out to 120 feet when you peer through the gem. The gem regains 1d3 expended charges daily at dawn.
Also in the 2014 rules (SRD 5.1).