Robust Nereid Emerald
Robust Nereid Emerald (#159616) 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 (120°, 75%, 34%) 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 violet. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
From the Latin robustus, of oak — implying strength combined with substance. As a color modifier, robust describes saturation combined with body: a robust burgundy, a robust olive. Sits in the bold-and-warm corner alongside strong and solid, with the slightly textural implication of a color that has substance behind the pigment.
Greek Νηρηΐς, sea-nymph-daughter-of-Nereus. As a color modifier, nereid implies a sea-nymph-and-Aegean-foam quality, the visual register of Hellenic-Nereid-and-Aegean-sea-nymph hand-sea-nymph-and-Aegean-foam Hellenic-Nereid-and-Aegean-sea-nymph-and-Poseidon-court nereid-and-sea-nymph-and-Aegean-foam surfaces under Hellenic-Nereid-and-Aegean-sea-nymph-and-Poseidon-court Aegean-island-and-rocky-cove sea-nymph-light. Sits at the modifier-and-myth end of the grid, parallel to nymph and dryad in usage.
A chromium-tinged variety of beryl — the gemstone mined from the Cleopatra-era Mons Smaragdus in Egypt, the Muzo deposits of Colombia, and the Sandawana mines of Zimbabwe. Emerald green refers to a high-clarity faceted emerald with strong color saturation: a saturated, slightly blue-shifted green with the gem's signature internal life. Cooler than fern, warmer than teal, with the heraldic weight of two thousand years of royal favor.
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.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
This color is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.