Magnetic polishes look so pretty in other people’s swatches. 🙁
These are polishes with ferromagnetic particles in the polish. You paint them on, then when they are still wet, hold a strong magnet over them to attract those (differently colored) particles in an appropriate pattern until the polish dries. The result is a cats-eye effect, where a stripe or curve or shape shows up and appears to move as you move the nail around. This lets you get cool chatoyance and galaxy effects.
In theory. In practice, I rarely get it to work. The result is weak or off-center, or just doesn’t look good, or I dunk the magnet in the wet nail polish, or whatever. I only remember ever getting really convincing results a couple of times. Usually it’s a fiddly, time-consuming disappointment.
So, uh, meet today’s PWI: The Lycurgus Cup, by Heather’s Hues!

If you look closely, you can see the brighter gold stripe down the centers of some nails. That’s actually the polish, not a reflection, but even moving it around under the light I can barely tell. I gave up and did the other hand without the magnet:

Basically indistinguishable.
To trouble-shoot: I could get a stronger magnet. I could build up a little stand so I could hold it near my finger without trying to hover it in midair. I could let it dry longer. I could use a different top coat. (Top coats partially dissolve the polish under them, so more magnet-ing is necessary at that stage.) I could have more patience for extremely fiddly shit. However, of all of those, the last is the least likely.
So now I am wearing a not-terribly-chatoyant bronzey-greeny-gold color, which is quite unobjectionable but does not do anything for me in my current mood, and I am disappointed. Bad Friday night time investment.
Also, my wordpress tag cloud has stopped updating. I don’t wanna debug my blog. I wanna drink something girly and go out with friends. Double bah.