Related Clues:

• Numismatist's classification
• Very hard to find
• Steak specification
• Most uncommon
• Once-in-a-blue-moon
• Special
• Like an ivory-billed woodpecker
• Far from plentiful
• Tuna order
• Nearly unique
• Seldom encountered
• Not at all well-done
• Hardly well-done
• Far from everyday
• ''Still mooing,'' at a steakhouse