What are the colours of the Magical Girl's Rings? I always thought the colour of the ring matched the Soul Gem. However after deciphering the runs on the ring I got with a Mami Soul Gem Necklace which said HOMURA, I looked up on the wiki and saw that Mami's is actually purple not yellow like her soul gem.

So I am wondering what are the colors of the rings for each of the magical girls?

EXTRA: I actually brought 6 Ring/Soul Gem Necklace with the 6th set having Homura's Soul Gem and a Green Ring.

EDIT: my mistake, it's a Green Soul Gem and Pink Ring
According to the list at the Madoka wiki:


Madoka Kaname (pink) - 
Homura Akemi (purple) - 
Mami Tomoe (yellow) - 
Sayaka Miki (blue) - 
Kyoko Sakura (magenta) - 


You can see in each of the images the name on the back corresponds with the name in the image (which I translated from this online translator). So it seems the colors are the same as the color of their soul gems. It seems the green soul gem also belonged to Madoka Kaname.

The list can also be seen in this Crunchyroll news post.