Hadean Reef
Hadean Reef (#0E5121) 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°, 71%, 19%) 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
Greek Hadean, of Hades — adjectival form of Hades. As a color modifier, hadean implies the deep cool-darkness of the classical-Greek underworld realms, with literary-poetic register. Sits at the deep-and-cool end of the grid, parallel to plutonian and Stygian in classical-mythological register.
The biological structure built by colonies of Anthozoa corals over millennia — Great Barrier Reef, Caribbean fringing reefs, Maldivian atolls. The color reef refers to the average coloration of a healthy mid-depth Caribbean reef: a soft, slightly muted blue-green with the optical complexity of light scattered through tropical water and refracted off thousands of small organisms. Cooler than seafoam, warmer than turquoise.
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.