all that glitters is not gold

All that glitters is not gold is a way of saying that just because something looks beautiful and precious, does not believe it is. This saying means that not everything that glitters, such as shiny, glittery, gold jewelry is not indeed as valuable as it might look, such as real 14K gold jewelry. It is often used in regards to actual valuable items like gold, diamonds, and other gemstones as well as a way to describe other things that might look precious but arent.