A bone necklace with a magical glass orb that contains a clear liquid and a piece of Aboleth brain.

While wearing it you gain advantage to history checks.  

Activate Analysis: You can use your Action or Bonus-Action to telepathically ask the necklace to analyze a creature within 60 ft. of you. A short rest regains 1 charge, a long rest regains both charges. 

You can ask for 2 of the following: Damage vulnerabilities, Damage Resistances, Damage Immunities, Condition immunities. 

Sometimes the Aboleth (DM) will provide more information, such as: Languages, Favoruite terrain, if they typically hunt alone or as a group etc. 

Semi-cursed and sentient: If you encounter a unique or rare creature, the necklace might activate on it's own to analyze it. You can prevent using the charge by beating a DC 14 charisma check. 

If the magical glass orb breaks or is targeted by dispell magic, the piece of Aboleth brain will dissolve and rejoin its Aboleth spirit on the Elemental Water Plane. This destroys the item. 

Notes: Advantage: History, Utility, Jewelry, Sentient, Symbiotic