As all relevant music videos must in 2012, the visual treatment for Rihanna’s Sia-penned, slightly underwhelming “Diamonds” takes place at the end of the world, or at least in a world where it is standard practice to roam around the streets covered in fire while alarming green clouds swirl above. (Could also be a gemstone-high. Fifty-fifty on that one.) Flowers fall out of their vases; time flies in reverse. And then two random horses show up and nuzzle each other for a while, because the new Rihanna-related video trend is to have wild and majestic animals running around the screen for no reason at all. (See also: the bull from “Take Care.”) Giraffe next? Hippo? Let’s run with this.