Related Clues:

• Describing a numismatist's treasure
• Least cooked
• Most collectible
• Least common
• Like AB negative, of all major blood types
• Most unusual
• Least lavish
• Least abundant
• Most infrequent
• Superlatively scanty
• Least available
• Least seen
• Superlatively scarce
• Most economical
• Most elusive