What would a mans 18ktgf onyx ring be worth?

The value of an 18kt gold-filled (18ktgf) onyx ring can vary significantly based on factors such as the craftsmanship, brand, and market demand. Generally, gold-filled jewelry is less expensive than solid gold but offers a similar appearance. On average, such a ring might range from $50 to $200, depending on the quality and design. For a more accurate valuation, it's advisable to consult a jeweler or appraiser.