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Authoritative Ametrine

#81177a
Notes

Authoritative Ametrine (#81177A) is a deep violet 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 (304°, 70%, 30%) 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 green. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#81177a
RGB
rgb(129, 23, 122)
HSL
hsl(304, 70%, 30%)
HWB
hwb(304 9% 49%)
OKLCH
oklch(42.9% 0.175 331.2)
P3
color(display-p3 0.4638 0.1312 0.4632)
HSV
hsv(304, 82%, 51%)
LAB
lab(31.08% 53.83 -30.63)
LCH
lch(31.08% 61.94 330.36)
CMYK
cmyk(0%, 82%, 5%, 49%)

Etymology

Authoritative
adjective

Latin auctōritāt-, authority — adjectival suffix -ive. As a color modifier, authoritative implies a saturated-and-formal-imperative quality where the hue carries decisional weight and institutional credibility. Sits at the bold-and-authoritative end of the grid, parallel to commanding and magisterial in usage.

Ametrine
noun

Naturally bicolored amethyst-citrine zoned quartz mined principally at the Anahí mine in eastern Bolivia. The deep-violet amethyst portion contrasts with the golden citrine zone in a single crystal. Ametrine color refers to the deep-violet amethyst zone of a polished Anahí-mine ametrine cabochon: a saturated, slightly cool deep violet with the glassy finish of iron-and-aluminum-substituted quartz under reflected light.

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 explore

Harmonies

Accessibility

Color-vision simulation

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.

#81177a
Original
#08407d
Protanopia
#3b4e78
Deuteranopia
#862649
Tritanopia
#353535
Achromatopsia
WCAG contrast

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.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon White
8.99:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.34:1

Wide gamut

Display P3 representation

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.

sRGB hex
sRGB hex
##81177A
Display P3
Display P3
color(display-p3 0.4638 0.1312 0.4632)
P3 has subtle headroomOKLCH chroma 0.175

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.

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