Open Sigil Teal

Old English open, unobstructed — used as a color modifier since the eighteenth century for hues that read as airy or uncrowded. Open blue, open green: moderate saturation combined with optical spaciousness, the slight visual breath of a hue that doesn't crowd the surface it covers. Sits at the crisp-bucket center alongside clear.

Latin sigillum, little-sign-or-seal. As a color modifier, sigil implies a magical-seal-and-grimoire-symbol quality, the visual register of medieval-grimoire-and-Solomonic-sigil hand-magical-seal-and-grimoire-symbol medieval-grimoire-and-Solomonic-sigil-and-Renaissance-occult sigil-and-magical-seal-and-grimoire-symbol surfaces under medieval-grimoire-and-Solomonic-sigil-and-Renaissance-occult parchment-and-vellum-and-quill grimoire-and-occult-light. Sits at the modifier-and-myth end of the grid, parallel to rune and omen in usage.

Anas crecca, the small dabbling duck whose male in breeding plumage sports a chestnut head crossed by a glossy green-blue stripe. The color refers to that stripe — the iridescent panel just behind the eye: a saturated, slightly muted blue-green with the optical depth of structural color rather than pigment. Cooler than cypress, warmer than cerulean, with the ornithological specificity of a color named for one feather of one bird.