Stygian Emerald
Stygian Emerald (#015215) 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 (135°, 98%, 16%) places it in the highly saturated band at a dark lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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
From the Greek Styx, the river of the underworld — used as an adjective in English since the seventeenth century to mean infernally dark. Stygian is the literary register for absolute darkness, deeper than inky and warmer than vantablack. Almost always reaches for poetic weight rather than precise reflectance.
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.
Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.