It seems there might be a small misunderstanding with the term "pix chest." The term you provided, "pix chest," is not a common English word or phrase. However, I believe you might be referring to "picks chest" or "pix" in a different context. If you meant "pix" as in pictures or images, that would be a different explanation altogether.
However, if you are indeed referring to "pix chest" in the context of coins or a chest that holds mint coins, I can provide a simplified explanation based on your provided definition.
Pix Chest (noun): A "pix chest" is a special box or container where coins that are made in a mint are kept before they are checked for quality (this checking is called "assay").
There are no specific idioms or phrasal verbs directly related to "pix chest," but in broader discussions about money or minting, you might hear terms like: - "Cash in" (to exchange something for cash) - "Break the bank" (to spend all your money)
While "pix chest" is not a commonly used term, understanding its meaning in the context of minting coins can be interesting, especially for those interested in numismatics.