Hardy Diatom
Hardy Diatom (#0B9E57) is a deep teal 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 (151°, 87%, 33%) 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
Old French hardi, bold / brave — past-participle of hardir (to make brave). As a color modifier, hardy implies a saturated-and-cold-resistant quality, the deep-rich color of Scandinavian-and-Russian boreal-forest-and-tundra outdoor-clothing. Sits at the bold-and-resilient end of the grid, parallel to tough and resilient.
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.