Beatrice Borromeo to Olivia Wilde: the most unique engagement rings

Some very romantic grooms-to-be have presented their leading ladies with some of the finest, and most unusual, pieces of jewelry anyone has ever seen – from classic pieces to custom shapes, colors and designs.
"Before the 1940s, diamonds were in fact not the traditional choice and engagement rings were used with precious stones," Holts Gems tells HELLO!. "Princess Diana and Kate Middleton brought back the colored engagement ring trend with their beautiful sapphire and diamond cluster ring, as did Grace Kelly with her lavish ruby and diamond ring."
As you contemplate the gorgeous gem you would want on your finger, take a look at these unique celebrity engagement rings.

The world's most famous bridesmaid is now a bride-to-be! Hedge fund manager James Matthews popped the question to Kate Middleton's little sister, Pippa Middleton, in July 2015 with a dazzling Art Deco-inspired Asscher cut diamond, which reportedly cost about $263,000. Following her engagement news, the socialite admitted, “[I] couldn't be happier” — and who could blame her with that rock!

Photo: Getty Images/GC Images

Beatrice Borromeo In the months leading up to her trip down the aisle with Pierre Casiraghi. The Italian beauty showed off her stunning ring. The unique pear-shaped diamond is surrounded by a halo of the gem and chunkier diamonds on the band.

Photo: Getty Images

Eva Longoria 'Telenovela' star Eva's boyfriend José Antonio Baston popped the question during a romantic trip to Dubai in December 2015 – and the actress couldn't resist sharing a pic of her stunning new ring, set with a large ruby surrounded by diamonds. "Ummmm so this happened....#Engaged #Dubai #Happiness," she wrote.

Photo: Instagram/@evalongoria

Anna Paquin In keeping with her rock chic style, Anna was presented with a truly unique ring by her 'True Blood' co-star Stephen Moyer. Instead of a traditional diamond, the actress was given a moonstone – said to bring good fortune and success in love.

Photo: Getty Images

Ashlee Simpson "My baby love and I are ENGAGED!!! Hallelujah Hawaii!!" Ashlee Simpson announced on Twitter alongside a snap of her new ring. The marquise-cut rock, which was accented with 140 diamonds and rich red rubies, was truly one-of-a-kind. Evan Ross had sought the help of jeweler Neil Lane to create the unique piece.

Photo: Twitter/@ashleesimpson

Jessica Simpson Eric Johnson sought the help of Neil Lane to create his engagement ring to Jessica Simpson – the same designer that his brother-in-law Evan Ross chose for his proposal to Jessica's sister Ashlee Simpson The rock is made of a central five-carat ruby, flanked by two pear-shaped diamonds on the side.

Photo: Getty Images

Christina Aguilera Matt Rutler spent over a year preparing his heart-warming Valentine's proposal and just as much thought went into designing the engagement ring. Christina shared a photo of her new sparkler on Twitter, with the caption: "He asked and I said Yes." Matt had taken two of Christina's favorite rings to create something that incorporated both designs into one. The result was an intricate oval-cut diamond ring featuring different stones that represent different aspects of Matt and Christina's relationship. "The actual band weaves and intertwines [the] diamonds," an insider told People. "Every connecting criss-cross symbolizes how their paths crossed." The rock also features nine special multi-color gemstones underneath the band that aren't visible when the ring is worn.

Photo: Getty Images

Amber Heard Amber Heard's love may not have gone the distance with Johnny Depp, but her huge diamond engagement ring is still impressive. Diamond experts have estimated the bauble to be a five-carat, oval diamond which could be valued at around the $100,000 mark.

Photo: Getty Images

Natalie Portman Benjamin Millepied designed Natalie Portman's engagement ring with the help of jeweler Jamie Wolf. The sparkler kept in line with Natalie's eco-friendly ideals, being made of a central antique round stone encircled by a halo of pavé conflict-free diamonds. "Ben was exceptionally thoughtful and dedicated and patient to make sure we had everything right," jeweler Jamie, who has provided items for Jessica Biel, Julia Roberts and Anne Hathaway among others, told InStyle. "We wanted everything about the ring to speak to things that are important to Natalie."

Photo: Getty Images

Halle Berry Olivier Martinez commissioned a unique piece of jewelery from his Paris neighbor, jeweler Robert Mazlo, to ask for Halle Berry's hand in marriage. The ring featured a central emerald flanked by two diamonds, set in a textured gold band. Robert is said to have sourced the ring from Colombia and included codes and symbols that only the wearer can decipher, in lieu of an inscription. The pair wed in 2013 but split two years later.

Photo: Getty Images

Alexis Bledel It took less than a year for Vincent Kartheiser to propose to his 'Mad Men' co-star Alexis Bledel. He presented the American beauty with a beautiful diamond ring that featured a vintage twist with its octagonal design.

Photo: Getty Images

Hayden Panetierre Hayden Panettiere flaunted her gorgeous split-shank diamond ring shortly after confirming her engagement to boxer Wladimir Klitsschko in October 2013. Her beau knew she would like the six-carat, emerald-cut ring – Hayden actually designed it herself with the help of Montblanc.

Photo: Getty Images

Jessica Biel Mom Jessica Biel was given a stunning six-carat ring from her singer love Justin Timberlake. The central cushion-cut diamond is surrounded by two rows of smaller diamonds, but the most unique part of the ring belongs to the intricate band that features the Greek evil eye. The blackened platinum color also gives the ring a vintage effect.

Photo: Getty Images

Carrie Underwood Bearing a similarity to Natalie Portman's ring, Carrie's sparkler also features a halo setting with a circle of diamonds wrapped around a yellow-and-white 12-carat stone. The rock, created by Carrie's hockey player beau Mike Fisher, with the help of the singer's favorite designer Johnathon Arndt, is estimated to be worth $805,000.

Photo: Getty Images

Lady Gaga First, Taylor Kinney proposed with a joke ring made of candy, then he pulled out this impressive sparkler. Lady Gaga's actual ring was a beautiful heart-shaped, 10-carat rock, valued at no less than $775,000. It featured the initials T and S in white diamonds on the band, as the singer's real name is Stephanie, separated by another heart-shaped symbol. Unfortunately the couple never made it down the aisle, going their separate ways in 2016.

Photo: Getty Images

Scarlett Johansson When Scarlett Johansson's French journalist fiancé Romain Dauriac popped the question, he presented the screen goddess with a gorgeous vintage Art Deco engagement ring that featured three circular diamonds set against a glittering rectangular base.

Photo: Getty Images

Olivia Wilde Bringing out the color in her eyes, Olivia Wilde's engagement ring picked out by her funnyman love Jason Sudeikis was the perfect choice. The ring features a central diamond surrounded by a halo of tiny emeralds, which catch the light as Olivia moves her hand. "All they know is that it went through Paris around 1921," Olivia told Brides of the vintage rock. "I love imagining the story of this ring. Who had it? It's a bit of an aqua emerald, not a deep dark green. Jason said it reminded him of my eyes, which is very sweet."

Photo: Getty Images

Mary-Kate Olsen One half of the Olsen twins, Mary-Kate was the talk of Hollywood when she showed off her engagement ring from Olivier Sarkozy for the first time in March. The ring, which featured a four-carat central diamond flanked by 16 sapphires and "petals" set with single-cut diamonds, was a fitting choice for Mary-Kate given her penchant for vintage clothing. It was reportedly bought at a Sotheby's auction in New York City for around $75,000, after being originally valued at between $37,000 and $55,000.

Photo: Getty Images and Sothebys

Kate Middleton Kate Middleton's colorful stunner brought back the colored engagement ring trend with her beautiful sapphire and diamond cluster ring.

Photo: Getty Images

Iggy Azalea Husband-to-be Nick Young chose a 10.43 carat Jason of Beverly Hills engagement ring for Iggy that was valued at $500,000. The ring features a huge, 8.15 carat Fancy Intense Yellow cushion cut center stone with 2.28 carats of white diamonds set onto 18 karat white gold. "Happiest Day #Isaidyes," Iggy wrote alongside a snap of her ring.

Photo: Instagram/@thenewclassic