All that glitters is not gold
Things that appear on the surface to be of great value may be quite worthless.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Idioms and Phrases with all that glitters is not gold
all that glitters is not gold
Something attractive is not always what it seems, as in This house is really beautiful, but a close look will show dry rot near the foundation—all that glitters is not gold. Aesop stated the same idea in two of his fables (c. 600 b.c.), and a version close to the current wording appeared in 1175.
The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.