Arabic (ركاز)- singular of rakaiiz– for all valuable objects underground. It includes all treasures (gold, silver, precious stones, etc.) whether buried in the earth naturally or by humans. For example, rizak could be gold coins that had been concealed for some time (maybe for years or even decades and centuries) until the time they were discovered by intentional digging or by mere chance, at a time there was no legal claimant thereof.

Rikaz includes, but is not confined to, kanz.