Conversation so far:
when do you give an eternity ring to your wife
An eternity ring is usually given by a spouse to their wife on the occasion of a significant anniversary, typically after 10 or more years of marriage.
where did the concept of the eternity ring come from
The concept of the diamond eternity ring was created in the 1960s by diamond merchant De Beers to avoid stockpiling of small diamonds.
where did the concept of the engagement ring come from
Anthropologists believe this tradition originated from a Roman custom in which wives wore rings attached to small keys, indicating their husbands' ownership.
do engagement rings have to have diamonds
Not all engagement rings have a single stone. Not all of them are with white diamonds. It all depends on taste.

Question: how much is the average cost
Self-contained rewrite: how much is the average cost of an engagement ring