Arcanum Rememorum

A spellcaster can use this magical eyeglass as a spellcasting focus without needing to attune to it. In addition, this eyepiece has the innate ability to cast the Detect Magic or the identify spell once a day. Once you use a charge to cast one of these spells using this eyepiece, it cannot be used to cast these spells again until the next dawn. 

This item also has the ability to see through low level magics used to obscure or hide text.

If a Wizard attunes to this item, they gain the ability to use the following attribute:

Tool of Refocus:

You can use the Arcanum Rememorum to alter your active spellbook and your memory. As part of a short rest you can forego any number of your prepared spells up to your spellcasting ability modifier, and prepare new spells of the same level. Spells changed in this way must be of 7th level or lower.

Once you have used this property, you cannot do so again until you finish a long rest.

(Credit for artwork and Tool of Refocus trait: @TheFantasticEmporium on Instagram)

Notes: by a wizard in order to use the Tool of Refocus feature., Detection, Utility, Focus, divination, enchantment