The Skewb Diamond is an ocatahedral puzzle. It is a Meffert's puzzle. There are 8 triangular (centre) pieces and 6 corner pieces. As you might expect, the puzzle is diamond-shaped.
If you've solved a skewb, you would solve this straight away - the solution is the same process. I find these puzzles fascinating but don't use them that much. Like the skewb, pyra/tetraminx, the fact that, with a little patience, you can solve it without knowing any method, means it's probably better to save pennies for something with a little more challenge.
The puzzle in the image is not the Meffert's one. It's fairly cheaply made and this comes across the second you pick it up and start turning it. It's one of many in the skewb family and worth it if you love your skewbs, otherwise save your pennies for something more challenging.