Yellow nail polish makes for an unusual but cool look for spring, especially if teamed with a cool green frock. Here are some examples of yellow nail polish:
The Opi Fiercely Fiona nail polish (see left) is a delicate lemon shade that looks classy and fresh due to how pale it is.
Amazon are selling it for $5.30. Click OPI Fiercely Fiona 0.5 oz. to buy.
The Opi Blonde Date Nail polish left has a gold tint to it. If you don't want to wear full-on gold but fancy something shimmering for evening wear, this shade is ideal.
OPI BLONDE DATE NAIL POLISH #LB1 Best price $8.50 from Amazon.com
The "bicycle yellow" from Creative Nail Design (left) is a much deeper richer yellow. It would go nicely with an orange or watermelon colored dress.
Creative Nail Design Bicycle Yellow #543 Best price $6.50 from Amazon.com
Rihanna has enhanced her nail polish with some nail art - personally I would have just had the plain yellow color.