The Jeweler is a place to stake JEWEL tokens for rewards which come from fee distribution. When you deposit your JEWEL with the Jeweler, you receive xJEWEL in exchange at a ratio that can be found in the Teller's menu. The ratio of xJEWEL to JEWEL grows over time. When you withdraw, you receive JEWEL in exchange at the current ratio. Since this ratio never decreases, you can never receive less JEWEL when you withdraw from the Jeweler than you deposited. You can deposit and withdraw at any time, with no fees.
The xJEWEL fund receives a share of fees from the DEX, liquidity withdrawals, and from in-game transactions. The fees collected from the DEX and liquidity withdrawals are not purely in JEWEL. When any player uses the claim function, the Jeweler will use these non-JEWEL tokens to market purchase more JEWEL, growing the total value of the fund and ultimately increasing the ratio of xJEWEL to JEWEL. In the Jeweler's menu, you can see your xJEWEL balance. You can also see the xJEWEL : JEWEL ratio, as well as a conversion to the total number of JEWEL represented by your xJEWEL balance, which increases as the xJEWEL : JEWEL ratio increases.
All rewards received from the Jeweler are unlocked right away and can be withdrawn at any time. Since Jeweler rewards are determined by transaction volume, the bank does not have a fixed yield.