Blue John may refer to:
- Derbyshire Blue John, a form of fluorite mined in Derbyshire, England
- Blue John Cavern, a cavern in Castleton, Derbyshire where fluorite is mined
- Blue John Canyon, a canyon in Utah, United States, site of the Aron Ralston accident
- Blue John (album), an album by organist John Patton
- Lance-Constable Bluejohn, a character in the Discworld series, a member of Ankh-Morpork City Watch
- Blue John Gap, a fictional location in Arthur Conan Doyle's short story "The Terror of Blue John Gap"
Famous quotes containing the word blue:
“Sometimes we see a cloud that’s dragonish,
A vapor sometimes like a bear or lion,
A towered citadel, a pendant rock,
A forked mountain, or blue promontory
With trees upon ‘t that nod unto the world
And mock our eyes with air. Thou hast seen these signs;
They are black vesper’s pageants.”
—William Shakespeare (1564–1616)