Sovereign Nautilus
Sovereign Nautilus (#1D853B) is a deep green with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (137°, 64%, 32%) 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 magenta. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old French soverain, supreme — derived from Latin super (above). As a color modifier, sovereign implies a saturated-and-royal-supremacy quality where the hue carries imperial-ruling-class register. Sits at the bold-and-imperial end of the grid, parallel to regal and imperial in tone.
Nautilus pompilius, the chambered nautilus — a living-fossil cephalopod whose mother-of-pearl interior shell is the source of abalone-style iridescence. Nautilus color refers to the inner shell of a polished nautilus: a soft, slightly cool pale blue-green with the iridescent satin finish of nacreous biomineral.
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.