Diamonds are forever, so a great way to mark the beginning of a long-lasting relationship is with a diamond ring. And when you’re rich and famous, the bigger the stone, the better. We tried to find out what are the most unique and expensive engagement rings ever bought – you can check out the results below.

9.-10. Hilary Duff – $1 million

Disney star and singer Hilary Duff started dating Canadian NHL player Mike Comrie in 2007. Comrie proposed to Duff in February 2010, while they were on vacation in Hawaii. The setting for the proposal was a balcony, at sunset, while the ring featured a princess-cut 14-carat diamond for which the hockey player spent $1 million.

9.-10. Catherine Zeta-Jones – 1$ million

Catherine Zeta-Jones and Michael Douglas met in 1998 during a film festival in France. They started dating in March 1999 and by New Year’s Eve they were engaged. Her engagement ring is a 1920s antique by Fred Leighton, featuring a 10kt stone surrounded by 28 smaller jewels. The glittering piece is estimated to be worth $1 million.

8. Kim Kardashian – $2 million

With the high profile relationship to Kanye West, it’s almost hard to believe Kim Kardashian was once married to basketball player Kris Humphries.

It was a whirlwind of an affair: they began dating in October 2010, got engaged the following May, got married that August and filed for divorce after just 72 days. Humphries proposed with a $2 million ring featuring 16.5-carat diamond at its center, flanked by a couple of smaller 2-carat diamonds.

6.-7. Anna Kournikova – $2.5 million

Despite only achieving modest success in singles tournaments, Anna Kournikova’s looks made her one of most famous athletes in the world at the beginning of the 2000s. She appeared in the video for the Enrique Iglesias song Escape in 2001, which is about the time they started dating – and even though their relationship has been somewhat shrouded in mystery, it seems they have been an item ever since. Their relationship seems to be destined to last, especially since Anna was spotted wearing a beautiful 11kt natural pink pear shaped diamond, valued at $2.5 million.

6.-7. Mariah Carey – $2.5 million

Mariah Carey and Nick Cannon started during the making of the music video for her song Bye Bye, which was filmed in Antigua. The pair clicked instantly and they eventually got married after just two months, on April 30 2008.

Despite the short notice, Nick Cannon still had time to get a beautiful Jacob & Co. 17-carat pink diamond ring worth a hefty $2.5 million.

5. Jacqueline Kennedy – $2.6 million

Five years after the passing of her first husband, President John F. Kennedy, Jacqueline Kennedy finally agreed to re-marry. This time it was to be with Greek-Argentine shipping magnate Aristotle Onassis.

The wedding ceremony took place on Onassis` private island of Skorpios, off the western coast of Greece. Equally impressive was Jackie’s ring, featuring the massive 40.42-carat marquise Lesotho III diamond. And while we don’t know how much the piece cost over 50 years ago, the ring sold at auction in 1996 for $2.6 million.

4. Melania Knauss – $3 million

Donald Trump is known for always thinking big and sometimes even being a bit over the top- and we’re not just talking about his business decisions. The Donald met Slovenian model Melania Knauss in the late 90s and eventually got engaged in 2004. The real-estate billionaire was no stranger to the situation, having been previously married twice, but the wedding ring he got for this occasion was the most impressive one of all – a 12-carat emerald-cut diamond worth $2 million.

3. Jennifer Lopez – $4 million

Jennifer Lopez has been engaged four times and on two of these occasions she received some amazingly expensive and gorgeous pieces of jewelry.

J-Lo started dating Ben Affleck in 2002 and the couple got engaged in November the same year, when the actor gave her a 6.1-carat Harry Winston pink diamond ring worth$2.5 million. They eventually broke up in 2004 and the Latin pop diva married singer Marc Anthony a few months later – who got her another impressive ring valued between $1million and $4 million.

But even with these rocks that she’s got, we’re sure she’s still Jenny from the block.

2. Paris Hilton – $4.7 million

Now in her thirties, the high-profile heiress doesn’t seem any to closer to settling down.

She was however close in 2005, when it was announced that Paris Hilton was engaged to Greek shipping heir Paris Latsios. It seemed to be great a match, both having similar backgrounds and even sharing the same name (cool coincidence or a sign? you decide!). The $4.7 million, 24-carat white diamond ring Latsios bought was also a good sign. However a few months later, in September 2005, the couple called off the engagement and the ring was auctioned off for charity.

1. Beyonce – $5 million

Beyonce and Jay Z seem to be close to the top of every celebrity list you can put together, so of course you’re going to find them here as well.

When Jay Z finally decided to put a ring on it, it was an 18-carat flawless octagon-cut diamond ring designed by jeweler Lorraine Schwartz. The stunning jewel was valued at an amazing $5million.