This is the OFFICIAL Puella Magi Madoka Magica ring that was released many years ago by COSPA and quickly sold out. They do occasionally re-release them but haven't in awhile and they come in limited quantities 

This Ring is for Homura Akemi. The Ring has been used for it bit, was but on a chain. It shows sign of wear such as needing a cleaning and polish since it is silver but nothing else is wrong with it. The color on the gem is not vibrant as it appears on the box though and is a little dull in color. I have confirmed with others that have purchased the same ring that is not flaw and all the rings appear like this. 

It is a Japan size 15, which is quite big, as you can see it is bigger then my thumb though I have tiny hands. Please check your ring size before purchasing though you can always wear this ring on a chain like I did! :) 

The original packaging and box is included. This is not a cheap chinese knockoff like the many you listed all over. 

Shipping is free but I will requite a signature confirmation when delivered. 

Item description from AMIAMI: 

Size: Japan Size 15 (Width 7mm, Inner Circumference Approx. 55.5mm)
Material: Silver 925 Oxidation Processed / Stone: Synthetic (Cubic Zirconia)

Initial release: 2011 Sept.

The Soul Gem worn by "Homura Akemi" from now famous Anime title "Puella Magi Madoka Magica" is here as a silver ring!
It is simple designed and can be worn in your daily lives! 

"Buy it and become a puella for me."