The Engagement ring in The Twilight Saga: Eclipse, which was given to Bella by Edward, is the true example of Eternity.

This ring was the true labor of Love. A prop master, several samples and five jewelers and a great research resulted in the formation of this Eclipse ring. Stephenie Meyer liked this glittering piece a lot.

How the ring can be made? This task was described by Meyer in her novel Eclipse. Prop master Grant Swain researched Jewellery of Victorian era before hiring the jewelers. Many prototypes of the ring were created but none of them impressed the Meyer.  As she had it in vision, she created a rough sketch of ring and then it was sent to the Jeweler of Portland, Rick Thurber,

Twilight Saga

who created the image of ring through computer to show the end result.
This stunning Diamond ring was then sent to the filming scene between Bella and Edward where everyone can see and adore it.