Ignore the link this takes you to. Finally found the original instagram post. This color is... drum roll.... Kiko - 365 tattoo rose. It's, of course, not currently being sold. I've seen a lot of posts that say that Essi angora cardi is similar, but that color seems darker to me.
Black nails with gold glitter on one nail. This is so easy to do, you don't even need a gold glitter nail polish! Simply paint your nails black and whilst it's still wet, shake some glitter onto it. So easy. And totally pretty!