Smashbox Sky is a very cool-toned, very light blue with a pearl finish. It is a permanent eyeshadow.
Sky is a muted, light-medium bluish-white with cool undertones and a pearly finish. It had nice pigmentation with a soft, blendable texture that was just a bit powdery--it was surprisingly good compared to how dusty other shades were (and pastels tend to be the worst offenders!). It lasted for seven hours on me. Sephora Blue Rhythm (LE, ) is more shimmery (95% similar). Dior Blue Garden #3 (LE, ) is more shimmery (90% similar). MAC Dark Energy #2 (LE, $21.00) is more shimmery, lighter, warmer (85% similar). Sephora Sweet Dreams (17) (DC, $10.00) is darker (85% similar). Dior Sugar Shade #1 (LE, ) is less shimmery, warmer (85% similar). MAC Dark Energy #3 (LE, $21.00) is more shimmery, darker, cooler (85% similar). See comparison swatches / view dupes side-by-side.