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:
“At twelve, the disintegration of afternoon
Began, the return to phantomerei, if not
To phantoms. Till then, it had been the other way:
One imagined the violet trees but the trees stood green,
At twelve, as green as ever they would be.
The sky was blue beyond the vaultiest phrase.”
—Wallace Stevens (1879–1955)