Foreboding Blueschist
Foreboding Blueschist (#21379B) is a true blue 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 (229°, 65%, 37%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old English fore-bēodan, to announce in advance — present-participle of forebode. As a color modifier, foreboding implies a deep-and-threatening atmospheric-anticipation quality, the dark cool-gray of advancing-cyclone storm-front cumulonimbus-base. Sits at the deep-and-threatening end of the grid, parallel to ominous and menacing in atmospheric tone.
A metamorphic rock — formed under low-temperature high-pressure conditions in subduction zones — characterized by the deep blue of glaucophane amphibole. The color refers to a freshly cut blueschist specimen: a soft, slightly cool deep blue with the metallic-gray-fibrous finish of crystallized amphibole.
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.