Open Gemini 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 gemini, twins-of-the-zodiac. As a color modifier, gemini implies a twins-and-air-sign-and-Mercury-ruled-mutable-air quality, the visual register of Castor-and-Pollux-Gemini-twins hand-twins-and-air-sign-and-Mercury-ruled-mutable-air Castor-and-Pollux-Gemini-twins-and-Argonaut-twins gemini-and-twins-and-air-sign surfaces under Castor-and-Pollux-Gemini-twins-and-Argonaut-twins late-spring-and-May-and-June mutable-air-sign-light. Sits at the modifier-and-zodiac end of the grid, parallel to castor and pollux 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.