Do real opals change color?

Opals are one of the most unique gemstones, not only because of their mesmerizing color, but also because of their chemical composition. ... The amount of water in opals will fluctuate over time based on factors like humidity, heat, sweat and contact with water. When an opal gains or loses water, its color will change.

Why has my opal turned yellow?

Hydrophane opals have the ability to absorb water or liquids, similar to a sponge, resulting in a change of color that may turn the opal translucent yellow or brown and the play-of-color to disappear temporarily. ... The color will return once the opal is fully and naturally air-dried.