Valentino makes a gorgeous rockstud iPhone case, but like almost all attractive phone covers, it's only available for Apple phones. :( Alas, my phone is a large Nexus 6P, and no one seems to make any attractive phone covers for it. So... here's a DIY. :)
Step 1: Bend the prongs on the back of the studs flat. I did this by pressing the prongs against a magazine on a table. The magazine protects the table from being scratched.
Step 2: Glue the studs to your phone cover with a strong glue like E6000 glue in the pattern shown. If the glue does not adhere to the particular rubber or plastic that your phone case is made of, reinforce studs by placing a small dot of Gorilla super glue on the phone case, and press the stud back on.
Or, if you are super dexterous and fast, you may choose to use Gorilla glue by itself. But, be warned, Gorilla glue dries VERY fast and very solidly, so adjustments are not as easy to make with this glue than E6000.
Tips: E6000 becomes useless if it has become thick and gooey; if this is the case, you will need to reinforce your studs with Gorilla super glue after the E6000 dries. Also, a plastic card or thick business card can be used to align the studs or clean up excess glue.
And, there you have it. A SUPER stylish phone case for very little money and effort! See the inspiration here. The original Valentino case retails $325. It has a similar look but is also in a luxurious calfskin instead of plastic, and I don't think the studs are just glued on like mine. It is one of the prettiest phone cases that I've seen, but unfortunately, they only make them for iphones.