All That Glitters

"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."

- The Merchant of Venice

Not everything that looks valuable on the surface is actually valuable. A bright facade on a house can conceal a rotting foundation. Makeup can conceal age and illness. A bright smile can hide deceit and hostility. Appearances can be deceiving. Whenever a character is deceived by surface appearances into overestimating the value of something this trope is in play.

In works that wish to teach An Aesop that material wealth is not the true wealth one should strive to attain, the "glitter" may very well be real treasure of considerable monetary value, set to deceive characters into choosing them over less obvious wealth, like love, friendship, or honor.

Anime and Manga

 * A little short story in the Ouran High School Host Club manga dealt with the host club trying to find the perfect soup that their principal had sampled when he was younger. Turns out it was a very common soup and that the one giving the soup to the principal would later be his wife.

Film

 * In Cat on a Hot Tin Roof the pivotal confrontation between Big Daddy and his son Brick invokes this trope. Brick tells his father that he isn't impressed with his vast wealth and all he wanted was a father not a boss. Big Baddy retorts that what was there that he didn't buy him when he was growing up? Brick then screams that you can't buy love and proceeds to destroy a vast collection of art that Big Daddy had purchased in an auction to show that none of the material stuff really mattered to him, he only wanted his father's love. Big Daddy says that he does love him he just wanted what was best for him because he grew up poor and his own father left behind nothing of value that would be worth remembering other than an old suitcase with a Military uniform in it. Brick disagrees saying that his grandfather left behind love for Big Daddy, moved to tears Big Daddy agrees and promises to try better as a father for Brick.
 * In the third Indiana Jones movie, Indiana Jones and the Last Crusade, Jones selects the grail by  an insult to carpenters everywhere, and in ignorance of the fact that Jews made a point of getting nice stuff specifically for Passover use, and didn't necessarily make every single thing they used by hand. But at any rate, everyone in the audience knew which cup it was going to be at first glance because of this trope. The only suspense was whether or not anyone besides Indy was aware of the trope.

Literature
"All that is gold does not glitter, Not all those who wander are lost. The old that is strong does not wither, Deep roots are not reached by the frost. From the ashes a fire shall be woken, A light from the shadows shall spring. ''Renewed shall be blade that was broken, The crownless again shall be king."
 * Inverted in The Lord of the Rings, in a poem about Aragorn, where the normal phrasing is reversed:


 * The original saying means "Just because it glitters doesn't mean it's gold," and this example means "Just because it doesn't glitter doesn't mean it's not gold.
 * Older Than Steam: The name of this trope comes from The Merchant of Venice by William Shakespeare (though, in the original play, the line was "all that glisters is not gold"). When Bassanio figures out the riddle, he gains Portia's hand in marriage, having learned that he should appreciate her for her mind rather than her beauty. (Of course, she was very wealthy, so in winning the hand he got the gold too.)

Live Action TV

 * A season two episode of Eureka uses this trope as its title and features a bacteria-eating virus which starts turning things to gold (and then to rust).

Western Animation

 * SpongeBob SquarePants uses a variation of the trope in one episode. Spongebob replaces his old spatula with a high-tech one, then crawls back to his old one after his new one literally declares it's too good for him. Spongebob even says "all that glitters is not gold". And the episode title is... *drumroll* All That Glitters.
 * The 2017 reboot of DuckTales actually subverts this. Scrooge McDuck and Gyro Gearloose have found many uses for gold in the miraculous technology they use. Which makes a lot of sense, actually - Scrooge is so familiar with the stuff, he's naturally done quite a bit of experimenting with it.

Real Life

 * Petroleum was often called "black gold" and "Texas tea" by prospectors. Sure, it's a black, dirty, smelly substance, but it's much, MUCH more useful and valuable than gold.
 * Abergris. This is, to put it bluntly, whale vomit. It is known to have a foul stench and looks like brown wax, yet it's incredibly valuable, used to make expensive perfume.