Step 1
Create a 17x17 image with wither a transparent or white background then zoom 500% into it.
Step 2
Form the outer shape of the Shuriken with a dark color of your choice. (I used #454545)
Step 3
Now use the Magic Wand Tool to select the inside of the outer shape.
Create a new layer and fill it with a color that is lighter than the outer shape's color, but not too light. (I used #545252)
Notice: The movement from the first color to the next color on the color picker.
Step 4
Now go to "Select > Modify > Contract" and set it to 1. Hit okay, create a new layer, and then fill the shown section with a color that is lighter than that of Step 3. (I used #655f5f)
Step 5
Create a new layer then make a small diamond with a hole the size of a pixel in the exact middle of the Shuriken. (Using the same color as in Step 2) Then shade around it with the color used in step 3. And you're done!
After Effects
To make it more real, you may want to cut out the middle pixel to have it see through or fill it in with white.
Here is what I ended up with:
