Formula X Freaky Like Freud Nail LacquerFormula X Freaky Like Freud Nail Lacquer ($12.50 for 0.40 fl. oz.) is described as a "periwinkle iridescent glitter." It's a cool-toned, gray-purple with holographic micro-glitter. It was semi-opaque after two coats. I also tried layering one coat over black, which gave a really pretty effect. If you were willing to apply three coats, I think it could also be worn on its own, otherwise I would recommend a solid base coat first. The consistency wasn't too thick or too thin, and I had no trouble applying the polish, either alone or as a top coat, as the glitter spread evenly. I don't know of a dupe based on what I've reviewed in the past, so if you happen to know of one, please feel free to suggest!