Related Clues:

• Masterpiece
• It may start as a grain of sand
• Something precious
• Oyster product
• Super Trouper Bert
• Oyster prize
• Necklace gem
• Oyster surprise?
• White gemstone
• 30th anniversary gift
• Sea discovery
• Birthstone in a shell
• Steinbeck opus, with "The"
• One of a strand
• Gem from an oyster