Royal Diatom
Royal Diatom (#329649) is a true green with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (134°, 50%, 39%) 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 magenta. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
The blue of European royal court dress and regalia from the late seventeenth century forward — the color of British peers' robes, French royal sashes, the lining of the crown-jewel cases. The color refers to a saturated, slightly violet-shifted blue with the matte finish of velvet or melton wool dyed to maximum intensity: deeper than cornflower, warmer than ultramarine, with the heraldic weight of a color reserved for monarchs and the official Crown.
Single-celled algae with intricate silica cell walls — among the most numerous photosynthetic organisms on Earth, producing roughly a quarter of global oxygen. The color refers to a diatom-bloom-tinted lake at midday: a soft, slightly cool deep blue-green with the optical complexity of suspended single-celled algae.
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.