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:
“But now Miss America, World’s champion woman, you take your promenading self down into the cobalt blue waters of the Caribbean and see what happens. You meet a lot of darkish men who make vociferous love to you, but otherwise pay you no mid.”
—Zora Neale Hurston (1891–1960)