The phrase "a dusky blue" is correct and usable in written English.
It can be used to describe a specific shade of blue that has a muted or dark quality, often evoking a sense of calm or depth.
Example: "The walls of the room were painted a dusky blue, creating a serene atmosphere."
Alternatives: "a muted blue" or "a smoky blue".
From the hammock on our balcony looking over a dusky blue and green panorama, the rest of the city seemed at a safe and manageable remove.
Perched on a wooden rail, waiting to be picked up by its new owner, is Mr. Iimura's most recent design — a dusky blue touring bike with a caramel-colored leather saddle, flat handlebars and shiny aluminum fenders.
Shouts all around for a mask were fruitless, and her lips and face were becoming a dusky blue.
Dye your hair a dusky blue.
It has a round wood frame and a scalloped back, and is upholstered in a dusky blue-gray velvet with a thick silvery fringe on the bottom.
He homed in on a dusky-blue silk cotton and pawed at a string of light-blue sequins coiled on top of it.
When Lt. John Charles Frémont's lips brushed her hand on that fateful day, Denton tells us, he was then a dubiously born 27-year-old hunk with "dusky" blue eyes, a "tanned face and flashing white teeth," just back from exploring the land between the Mississippi and Missouri Rivers.
Example: "...the oil has ruined several slit-to-the-waist dresses in a silk crepe de Chine that shimmers like a wicked smile in peach, auburn, dusky blue and lemp".
Kate, wearing a duck-egg blue empire-line Emilia Wickstead cocktail dress and dusky blue heels, said: "I am a firm believer in the power of art to make a difference and The Art Room is doing that on a daily basis.
The sky was a dusky, deepening blue behind her, with massive buildings looming among the city lights.
Ask for a front-facing room to capture the spectacular sunrise over the dusky Blue Ride.
