Emma Roberts made "smoky quartz" hair a thing, and the rock-inspired hair hues are just beginning. Suddenly, the color everyone's talking about is "geode." You know geodes: they're those gorgeous ...

There are plenty of hair trends out there on Instagram. People have found ways to make their hair look like graffiti, or glow in the dark, or even make it look like denim. I have a suspicion that if ...