treasure house

a building, room, or chamber used as a storage place for valuables; treasury.

a place or source where things of value or worth may be found: Books are the treasure house of ideas.

Origin of treasure house

late Middle English word dating back to 1425–75

It was this part of the temple, then, that the Greeks called the treasure-house.

A history of art in ancient Egypt, Vol. I (of 2) |Georges Perrot
The landscape seems to contain nothing but rocks and towering crags, a treasure-house for those 20 who mine.

The Forester's Daughter |Hamlin Garland
The cobra then brought from his treasure-house a number of diamonds and rubies and other precious stones.

Wonder Tales from Many Lands |Katharine Pyle
Some say it is a treasure-house of the Moors, where they have left their wealth.

Orientations |William Somerset Maugham

He was a treasure-house of Attic style and ancient maxims, and eminently useful to orators who liked quotations.

Euripedes and His Age |Gilbert Murray