· some of the most expensive modern engagement rings include kim kardashians 15-carat, $8 million diamond and mariah careys 35-carat emerald cut ring. Theres a long history of expensive celebrity. · the most expensive engagement ring is the cartier ring , once owned by grace kelly. Lab-grown diamonds are cheaper on average than natural diamonds by 50% or more. Here we will discuss those love birds who got rare, sophisticated, exclusively designed, and expensive diamond rings when they proposed. There are a bunch of celebrities here who went all out while choosing the engagement ring and made the news. The $46. 1 million (in inflation-adjusted 2024 dollars) ring now belongs to the house of grimaldi of the principality of monaco and is considered the most expensive engagement ring in the world. · fancy colored diamond rings are the most expensive, with an average cost of $23,525.
