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Effulgent Quell Turquoise

#21e6d4
Notes

Effulgent Quell Turquoise (#21E6D4) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (175°, 80%, 52%) places it in the highly saturated band at a mid 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.

HEX
#21e6d4
RGB
rgb(33, 230, 212)
HSL
hsl(175, 80%, 52%)
HWB
hwb(175 13% 10%)
OKLCH
oklch(83.3% 0.143 184.7)
P3
color(display-p3 0.4275 0.8889 0.8306)
HSV
hsv(175, 86%, 90%)
LAB
lab(82.74% -48.40 -4.03)
LCH
lch(82.74% 48.57 184.76)
CMYK
cmyk(86%, 0%, 8%, 10%)

Etymology

Effulgent
adjective

Latin effulgēns, shining-out — present-participle of effulgere, sharing root with fulgor (lightning). As a color modifier, effulgent implies a saturated-and-radiating-light-out quality, the bright color of Renaissance-Madonna halo-and-aureole gold-leaf-and-pigment emission. Sits at the bright-and-saturated end of the grid, parallel to resplendent and radiant in usage.

Quell
modifier

Old English cwellan, to-kill-or-suppress. As a color modifier, quell implies a stilled-and-suppressed-and-pacified quality, the visual register of vesper-bell-and-curfew-quell hand-stilled-and-pacified-and-suppressed vesper-bell-and-curfew-bell-and-night-watch quelled-and-stilled-and-suppressed surfaces under vesper-bell-and-curfew-bell-and-night-watch hush-and-stillness-and-quiet bell-tower-and-monastery light. Sits at the modifier-and-mood end of the grid, parallel to hush and lull in usage.

Turquoise
noun

The hydrated copper-aluminum phosphate mined in Persia and the American Southwest for thousands of years — the firuze of Iran, the chalchihuitl of Mesoamerica, the heart of Pueblo and Navajo silverwork. The color refers to a fine Sleeping Beauty turquoise from Arizona: a saturated, slightly green-shifted blue with the slight matrix of host-rock veining. Brighter than persian, lighter than cerulean.

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.

#21e6d4
Original
#dad8d3
Protanopia
#c2c6d6
Deuteranopia
#00ebe0
Tritanopia
#bbbbbb
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).
Failon White
1.57:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
13.33:1

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
##21E6D4
Display P3
Display P3
color(display-p3 0.4275 0.8889 0.8306)
P3 has subtle headroomOKLCH chroma 0.143

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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