Acid Hiddenite
Acid Hiddenite (#63BE67) is a true green 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 (123°, 41%, 57%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. 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
Latin acidus, sour — sharing root with English acrid and acerbic. As a color modifier, acid implies a saturated-and-citric-and-zingy quality, the bright color of lemon-and-lime citrus-fruit-flesh and acid-yellow fluorescent-pigment surfaces. Sits at the bright-and-cool end of the grid, parallel to acidic and electric in usage.
The chromium-rich green variety of spodumene — discovered in 1879 in Hiddenite, North Carolina, where it was named for mineralogist William E. Hidden. The color refers to a faceted hiddenite: a saturated, slightly cool yellow-green with the gem's signature internal life. Cooler than tsavorite.
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.