Around early 2014 Kate started wearing this ring.
From the website: ” “Brilliant-cut micro-pavé white diamonds with a cumulative weight of 0.23 carats are meticulously hand set into this 18ct white gold eternity ring, putting a uniquely modern twist on a classic piece of jewellery.”
The ring is set apart from typical eternity rings by its firm band of white gold on either side of the diamonds. Most eternity rings feature unbordered diamonds.
Here it is on Kate:
This item retails for $1,400.