all that glitters is not gold
Definition from Wiktionary, the free dictionary
- Things that appear valuable or worthwhile might not actually be so, things that look nice might not be as good as they look.
things that look nice might not be as good as they look
- Gregory Y. Titelman, Random House Dictionary of Popular Proverbs and Sayings, 1996, ISBN 0-679-44554-4, p. 9.