hens' teeth

Something very scarce (because hens have no teeth). Typically used in phrases like "rarer than hens' teeth." I can hardly believe your brother got an A on his final exam—grades like that are rarer than hens' teeth for him!

Common Names:

Name	Pronounced	Usage
Yaropolk	-	Medieval Slavic
ÖRjan	UUR-yahn	Swedish
Venka	VEN-kah	Esperanto
RagnbjÖRg	-	Ancient Scandinavian
GÖKsu	-	Turkish
Shereen	-	Persian