crock of gold

a valuable but elusive treasure

Japanese Meaning

価値はあるが、なかなか手に入れられない、または捕らえにくい宝物

何年もの捜索の末、古い地図はついに丘の洞窟に隠された貴重でつかみどころのない宝物へと彼らを導いた。

Sense（1）

a valuable but elusive treasure

"It was like turning up a crock of gold," he remembers. "It was absolutely wonderful." http://www.bbc.co.uk/news/magazine-12266109

crocks of gold

（ plural ）