The Rainbow Bluet is one of my favorite Odonates -- a damselfly colored like a tropical bird. The most reliable place I know to find them is Lake Louise State Park, near the Iowa border, where they coexist with Orange Bluets and purple Variable Dancers. The fact that all this color occurs in Minnesota seems like some kind of mistake.
Male Rainbow Bluets have a blue taillight and a more or less greenish thorax -- sometimes blue with just a drop of green in it, sometimes a beautiful seafoam color. From a distance they can be hard to distinguish from Eastern Forktails.
Close up, they're easily recognized by their pale yellow legs, yellow-orange faces, and color-wheel eyes.
From above they have a scratch art look, with thin stripes of bright color showing through a black background.