Possible Clues:

• Gem of a small part?
• Artist shuns photo equipment first to observe film role
• Design in relief
• Showed up with nothing for gemstone
• Hitchcockian walk-on
• "Word Up" R&Bsters
• Item of jewellery with carved portrait
• Actor's brief role had no outcome?
• Jewellery item — small dramatic role
• Short piece arrived with ring attached