Assured Glide Ruby
Assured Glide Ruby (#951618) is a deep red 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 (359°, 74%, 34%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary cyan. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old French aseürer, to give assurance — past-participle of assure. As a color modifier, assured implies a saturated-and-confident quality where the hue carries unwavering certainty about its own visual identity. Sits at the bold-and-confident end of the grid, parallel to certain and poised.
Old English glīdan, to-move-smoothly. As a color modifier, glide implies a smooth-and-silent-and-frictionless quality, the visual register of swan-and-skater-glide hand-smooth-and-silent-and-frictionless swan-and-skater-and-soaring-albatross glided-and-smooth-and-silent-and-frictionless surfaces under swan-and-skater-and-soaring-albatross frozen-pond-and-Hyde-Park-Serpentine-and-open-ocean smooth-flight-light. Sits at the modifier-and-mood end of the grid, parallel to float and hover in usage.
From the Latin ruber — simply, red. The gemstone is a chromium-tinged corundum, harder than anything in nature except diamond, and so saturated that a fine Burmese pigeon's blood ruby at auction outpaces a comparable diamond by weight. The color borrows the gem's confidence: a clear, glassy red without the brown of garnet or the blue of crimson.
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.