Opals! Photonic crystals! Structural color! Opals are examples of natural photonic crystals. They are composed of small silica nanoparticles ranging in size from 50-300nm, and packed tightly together ...

We’re settling this hot debate once and for all. Here's everything you need to know about the opal jewelry trend.

Opals, associated with the zodiac sign Libra, are known for their emotional healing and creativity-boosting powers. Artists ...