Compared To Other Colors Found In Nature, True Blues Are Pretty Rare—but The Indigo Milk Cap (Lactarius

Compared to other colors found in nature, true blues are pretty rare—but the indigo milk cap (Lactarius indigo) has just that! This vibrant mushroom gets its color from a pigment that is a derivative of guaiazulene, a dark blue crystalline hydrocarbon. You would think that its blueness is a marker for toxicity, but the mushroom is actually edible—although its color fades to a grayish hue when it’s cooked.

Photo: Andrey Loria, CC BY-SA 4.0, iNaturalist