3 coats, no topcoat. I have posted about this one before, but I love holographics so much I had to post another! What I love about these from the Kaleidoscope Collection is they fare well even in dim light. I can see rainbows indoors without any sunlight.
This last picture the color washed out a lot but rainbow is still there! I put a clear topcoat on 1 finger (not pictured) and the rainbow disappeared so definitely avoid a topcoat if possible.
It looks silver but there's a pink/lavender hue to it. Sadly these are discontinued but you still might be able to find some stock at etailers.