Hi everyone,
The grey nails I was wearing are perfect, seriously. But it's summer... and I wanted something to scream SUMMERRRRR, so I added some cheap nailpolish (unbranded) with holograpic sparkles and particles. I placed layer one on 2/4th of my nail, then layer two on 1/2th of my nail, and then the last coat on the tips only, making most of the "jewels" end up on the tips. I love this gradient on my nails.
Lamp light: 
Flash light: 
it
That is a fantastic idea for the grey nails. Looks really pretty.