Frank Slab Lazuli
Frank Slab Lazuli (#059FA8) is a deep cyan 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 (183°, 94%, 34%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
From the Old French franc, free, sincere — used as a color modifier since the seventeenth century for hues that read as direct and unhedged. Frank red, frank brown: moderate-to-high saturation combined with optical directness. Sits at the crisp-bucket alongside direct and honest.
Old French esclape, splinter / slab. As a color modifier, slab implies a flat-thick-stone-or-wood quality, the visual register of Cotswold-and-Yorkshire-flagstone-and-slab hand-quarried-and-flat-thick stone-and-timber-and-marble hand-quarried-flat-thick-slab surfaces under Cotswold-and-Yorkshire flagstone-and-slab quarry-light. Sits at the modifier-and-texture end of the grid, parallel to plate and tile in usage.
Passerina amoena, the lazuli bunting — a North American songbird whose males display saturated deep-blue plumage with white wing bars and chestnut breasts. Named for the gemstone (lapis lazuli) the bird's plumage resembles. The color refers to a male lazuli bunting in breeding plumage: a saturated, slightly cool deep blue.
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.