All that glitters is not gold
Not everything that is shiny and superficially attractive is valuable.
The original form of this phrase was 'all that glisters is not gold'. The 'glitters' version long ago superseded the original and is now almost universally used.
Shakespeare is the best-known writer to have expressed the idea that shiny things aren't necessarily precious things. The original editions of The Merchant of Venice, 1596, have the line as 'all that glisters is not gold'. 'Glister' is usually replaced by 'glitter' in modern renditions of the play:
O hell! what have we here?
A carrion Death, within whose empty eye
There is a written scroll! I'll read the writing.
All that glitters is not gold;
Often have you heard that told:
Many a man his life hath sold
But my outside to behold:
Gilded tombs do worms enfold.
Had you been as wise as bold,
Young in limbs, in judgment old,
Your answer had not been inscroll'd:
Fare you well; your suit is cold.
Various different ways of expressing the idea that 'all that glitters/glisters is not gold' were in general circulation well before Shakespeare's day and it was a common enough notion to have been called proverbial by the 16th century. The 12th century French theologian Alain de Lille wrote "Do not hold everything gold that shines like gold". Geoffrey Chaucer also expressed the same idea in Middle English in the poem The House of Fame, 1380 - "Hit is not al gold, that glareth". Nevertheless, it is Shakespeare who gave us the version we now use.
The 'glitters' version of this phrase is so long established as to be perfectly acceptable - especially as 'glisters' and 'glitters' mean the same thing. Only the most pedantic insist that 'all that glisters is not gold' is correct and that 'all that glitters is not gold', being a misquotation, however cobweb-laden, should be shunned. John Dryden was quite happy to use 'glitters' as long ago as 1687, in his poem The Hind and the Panther:
For you may palm upon us new for old:
All, as they say, that glitters, is not gold.
See other phrases and sayings from Shakespeare.
See also: the List of Proverbs.