A high-quality, square, professional audiobook cover illustration (1024x1024). The image should evoke the mood of a classic, slightly melancholic, yet beautiful fable set in a tropical coastal environment. The primary focus is a single, luminous, impossibly large, perfectly formed pearl resting on a bed of dark, wet sand. The sand should have subtle textures and be slightly reflective, hinting at being recently exposed by the tide. Surrounding the pearl, and partially obscured by its brilliance, are hints of the shallow, turquoise ocean water, with faint, ethereal rays of sunlight dappling its surface from above. The overall color palette should be rich but subdued: deep blues and greens for the water, warm earthy browns and blacks for the sand, and a pure, intense, soft white-gold glow emanating from the pearl. The mood should be one of awe, hidden danger, and profound, solitary beauty. The composition should be centered on the pearl, drawing the viewer's eye immediately to its luminescence, with the surrounding elements providing context and atmosphere without being overly detailed or distracting. No text, no letters, no words, no title, no author name.