Silken Jade

#11a39e

A cyan that is muted. It is light — black text sits on it comfortably, white text does not.

Hex

#11a39e

RGB

17, 163, 158

OKLCh

64.7% 0.109 190.9°

CIELAB (D50)

60.3, -36.7, -7.9

What is true of this colour, and of no other

8 other named colours sit within ΔE00 2 of it.
It uses 98% of the chroma sRGB can show at this lightness and hue — close enough to the boundary that a wider display would show it slightly more vividly.
As text on white it measures APCA Lc 57.5; on black, Lc -44.2. The sign is the polarity, which the WCAG ratio discards.
Built into an eleven-step scale, 10 of the 10 adjacent pairs stay ΔE00 2 apart — see the ramp.
protanopia and deuteranopia and tritanopia shift it by ΔE00 24.7 and 26.4 and 35.4 — no red cone.

Text on this colour

White text

3.11:1 — large text only

Black text

6.76:1 — passes AA

Black text is the better of the two at6.76:1. That is enough for body text.

As text on white, it needs to change

#008581 is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved, and some saturation was given up to stay inside sRGB.

Try it against your own background

The same colour, with one cone missing

As you see it

#11a39e

protanopia

#9b9b9e · ΔE00 24.7

deuteranopia

#8c8ca0 · ΔE00 26.4

tritanopia

#7878ff · ΔE00 35.4

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isAqua Velvet at ΔE00 0.553: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

Aqua VelvetΔE00 0.553 · #00a29e
JadestoneΔE00 0.986 · #01a6a0
Ceramic Blue TurquoiseΔE00 1.157 · #16a29a
Talismanic TealΔE00 1.276 · #159f9b
Royal CloakΔE00 1.317 · #16a5a3
Grecian IsleΔE00 1.508 · #00a49b
Baltic TurquoiseΔE00 1.855 · #00a49a
Sea KaleΔE00 1.954 · #30a299
Spectra GreenΔE00 2.171 · #00a096
Tyrolite Blue-GreenΔE00 2.203 · #00a499
Baltic GreenΔE00 2.454 · #3aa098
Caribbean TurquoiseΔE00 2.542 · #009d94

12 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.