Formula:Fe2O3
Mohs: 5.5 to 6.5
This glittery stone is iridescent hematite, also called turgite. It’s a rare form of the mineral, and for a long time, we had no idea what gave it that signature color palette. Like, hematite is the same thing chemically as rust. So researchers were pretty invested in figuring out how these particular hematites got their makeover.
And it turns out that the color isn’t pigment-based at all. It’s the result of thin film iridescence, which is the same phenomenon that makes oil slicks so mesmerizing. Basically, the thin coating on the outside refracts light differently than the material underneath, and the two wavelengths basically fight with each other. It’s an example of structural color, where an object’s colorful appearance is the result of its texture, not a pigment. The result is this multi-color effect that makes iridescent hematite utterly gorgeous.