Yes, almost all major cruise ships have dedicated onboard jewelry boutiques selling everything from affordable souvenirs to high-end luxury pieces. Popular brands like Effy and Diamonds International often have a permanent presence on ships, frequently hosting "educational" seminars or "unveiling" events to attract shoppers. You will find a wide array of precious stones, including diamonds, tanzanite (a cruise ship favorite), and sapphires, often marketed as "tax and duty-free." However, experts caution that while the "no tax" aspect is true, the prices aren't always a "deal." Because you are a "captive audience," initial markups can be high, and the "appraisal" provided on the ship often reflects a high retail replacement value rather than what you could resell the piece for later. If you plan to buy, it is wise to research gemstone prices beforehand and remember that you are paying a premium for the convenience and the memory of the vacation rather than finding a secret wholesale bargain.