Useful Pollux Lagoon

Latin ūsus, use — adjectival suffix -ful. As a color modifier, useful implies a clear-and-purpose-serving quality where the hue carries the visual register of helpful-and-supporting design-element. Sits at the crisp-and-functional end of the grid, parallel to practical and serviceable in usage.

Greek Πολυδεύκης, Gemini-twin-and-immortal-boxer. As a color modifier, pollux implies a Gemini-twin-and-immortal-brother quality, the visual register of Gemini-Pollux-and-Castor-twin hand-Gemini-twin-and-immortal-brother Gemini-Pollux-and-Castor-twin-and-Argonaut pollux-and-Gemini-twin-and-immortal-brother surfaces under Gemini-Pollux-and-Castor-twin-and-Argonaut spring-Gemini-and-Bortle-1-sky stellar-twin-light. Sits at the modifier-and-cosmic end of the grid, parallel to castor and spica in usage.

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.