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Authoritative Ametrine

#66328c
Notes

Authoritative Ametrine (#66328C) is a true indigo with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (275°, 47%, 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 lime. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#66328c
RGB
rgb(102, 50, 140)
HSL
hsl(275, 47%, 37%)
HWB
hwb(275 20% 45%)
OKLCH
oklch(42.9% 0.147 308.0)
P3
color(display-p3 0.3733 0.2068 0.5305)
HSV
hsv(275, 64%, 55%)
LAB
lab(31.81% 40.18 -40.95)
LCH
lch(31.81% 57.37 314.46)
CMYK
cmyk(27%, 64%, 0%, 45%)

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.

#66328c
Original
#00498f
Protanopia
#234b8a
Deuteranopia
#60445a
Tritanopia
#444444
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
8.75:1
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
2.40:1

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
##66328C
Display P3
Display P3
color(display-p3 0.3733 0.2068 0.5305)
P3 has subtle headroomOKLCH chroma 0.147

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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