Wondrous item, rare
Objects that lie beneath the plate, and objects within the chest, crate, or drawer the plate is set upon, are left out of every count. A creature counting or listing the place omits them, arrives at a number that is short by their number, and finds nothing wanting; a written tally, inventory, manifest, or receipt made of that place omits them in the same way, whoever writes it and however carefully. No saving throw is offered, because nothing is done to the creature: the objects are not hidden, not silenced, and not made invisible.
A creature that already knows the object and is looking for that object finds it, picks it up, and uses it. It will not afterwards be able to write it into a list.
Magic that finds a thing by naming it, locate object among the rest, fails while the thing lies beneath the plate.
An object left beneath the plate for 30 days stops appearing in written records of ownership everywhere: bills of sale, pledge-books, wills, freight books, and the registers of the offices of this city. The entries are not struck through. They are simply not there when looked for, and the clerk who looks does not think it strange.
Lifting the plate does not bring the entries back. Title to such a thing has afterwards to be made again from the beginning, by oath and by witnesses, and in this city that costs more than most of the things it is worth doing for.
Where the plate has stood in a hall that is counted nightly, the count has come out low, and the difference has been carried in the book as an error of the weather.
Source: Provenance — The Quist Sale