Bluebell Flames

"she whipped out her wand, waved it, muttered something, and sent a jet of the same bluebell flames she had used on Snape at the plant. In a matter of seconds, the two boys felt it loosening its grip as it cringed away from the light and warmth."

- Hermione using the spell against the Devil's Snare.

Bluebell Flames, also known as Cold Fire, is a charm that conjures bright blue, waterproof flames.

Although the fire produced can be scooped up and carried about in a jar, it can still burn things.

Known practicioners

 * Hermione Granger
 * Remus Lupin.

Known uses

 * Hermione Granger used the spell at least thrice in the 1991-1992 school year; firstly to keep her, Harry Potter, and Ron Weasley warm in the Entrance Courtyard, the second to set Severus Snape's robes aflame in order to distract him, believing that he was trying to jinx Harry, and the third time to burn some Devil's Snare that was attacking Ron and Harry.
 * She used it again the next year to produce some flames over with to illicitly brew a Polyjuice Potion

Behind the scenes

 * In the film, this spell was replaced by Lacarnum Inflamarae and Lumos Solem respectively.
 * In the seventh film, Ron tells Harry that he always liked these flames. In that film, they're the colour of normal fire, though in the book they're still blue.
 * The video games make it seem like Incendio is the bluebell flames spell. However, Incendio makes normal fire, not blue fire.
 * Hand-held flames may be a variation.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Goblet of Fire (video game)
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Pottermore
 * Harry Potter Trading Card Game

Notes and references
Flammes bleues Fiamme azzurre