Thunderous Coquille
Thunderous Coquille (#691B54) is a deep magenta with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (316°, 59%, 26%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary green. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old English thunor, thunder — adjectival suffix -ous, sharing root with German Donner and Old Norse Þórr (Thor). As a color modifier, thunderous implies a deep-and-rumbling-and-imposing-cool quality, the dark cool-gray of cumulonimbus-tower-base storm-cloud directly overhead. Sits at the deep-and-turbulent end of the grid, parallel to stormy with auditory-resonance overtone.
French coquille, shell — particularly the coquille Saint-Jacques (Pecten maximus, scallop shell) whose interior surface displays a deep-magenta-to-pink iridescent nacre. Coquille color refers to a freshly opened Pecten maximus shell-interior in raking light: a saturated, slightly cool deep magenta with the iridescent satin finish of structurally colored aragonite-nacre. The shell is the heraldic symbol of Saint James of Compostela.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.