Eternity rings explained: full, half, and sizing

An eternity ring is a band set with a row of matching stones. GIA describes eternity, or anniversary, rings as rings "with diamonds around the entire band." The one thing to know before you buy: GIA says these rings can be very hard to resize. This guide covers the two main styles, sizing, settings, and how an eternity band sits with other rings.

What is an eternity ring?

A full eternity ring carries stones the whole way around the band. GIA's ring stacking guide says more couples now add an eternity ring as a third ring in their stack, and it links the ring with a significant anniversary. You can also wear one on its own.

How does a half eternity ring differ?

A half eternity ring keeps the same row of stones across the front of the band and leaves the back as plain metal. That is our plain description of how sellers use the term. We found no neutral source that defines it, so we cannot point you to a fixed meaning. A half eternity band can also look much like a diamond wedding band, so look at photos of the whole band, including the back, before you buy.

When you shop, ask how far the stones run around the band. A listing that says "eternity" may mean either style.

Can you resize an eternity ring?

Plan as if you cannot. GIA says: "It also can be very difficult to resize eternity/anniversary rings (that is, those with diamonds around the entire band)." It says pavé and channel settings are hard to resize too, and both appear on eternity bands.

GIA says a typical ring can go up or down a size or two, and that rings with pavé or bead-set diamonds on the band require more work. We have no neutral source that says how far a half eternity band can be resized. Ask the jeweler, in writing, before you buy.

How do you get the size right first?

Measure with care, because you may not get a second chance. GIA prefers a jeweler measuring with finger gauges, a set of metal bands in half-size steps. It says temperature, humidity, altitude, and time of day can all change finger size.

Width matters on a stone-set band. GIA says: "Rings with wide shanks usually need to be a bit larger, as they will fit more snugly." It also says a set of rings worn together that is wider than 4 or 5 mm needs special thought. Our ring sizing guide and ring size chart cover measuring.

Which settings hold the stones on an eternity band?

GIA says "Different settings offer different degrees of protection." GIA's stacking guide mentions channel-set eternity bands, where the stones sit in a groove of metal.

GIA says vulnerable points or corners "are better protected with bezels, partial bezels, or V-shaped prongs." GIA suggests a jeweler check prongs every six months. Our ring settings guide compares the styles.

How does an eternity ring sit with other rings?

GIA's stacking guide says the traditional order puts the engagement ring above the wedding band, with the eternity ring placed above the engagement ring. That is a tradition, not a rule.

GIA's buying tips say to make sure rings worn together match in silhouette and fit together. An eternity band holds many stones, so its listed weight is a total carat weight: GIA defines that as the combined weight of every diamond in the ring.

Sources: GIA 4Cs blog, How to Determine Ring Size: Tips and Ring Size Chart; GIA 4Cs blog, Ring Stacking Guide; GIA 4Cs blog, 10 Tips for Buying a Diamond Engagement Ring; GIA 4Cs blog, More than the Mohs Scale: Understanding Gem Durability; GIA 4Cs blog, How to Protect Your Diamond Engagement Ring; GIA 4Cs blog, Nine Things About Diamond Carat Weight You Need to Know.