Are you planning to propose, but haven't found quite the right diamond?

Well, get out your chequebooks, folks -- because the world's most insanely beautiful diamond is being auctioned off today!

The Archduke Joseph diamond weighs in at a whopping 76 carats, and used to belong to Austrian royalty. It's a cushion cut, and is rated 'D' grade -- which we think just means it's really, really sparkly.

See it in action below -- and prepare to be mesmerized by the twinkling facets! Marvel at the perfect clarity of this (literally) flawless gem! Feel nauseous when you hear the auction estimate -- 25 million dollars!

RELATED: Ridiculously Large Celebrity Engagement Rings

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  • Beyonce & Jay-Z

    In 2007, Jay-Z gave Beyonce this 18-carat diamond set in platinum designed by Lorraine Schwartz which reportedly cost $5 million! (Getty photos)

  • Kate Middleton & Prince William

    For their much anticipated engagement in November 2010, Prince William gave Kate Middleton the same ring that was worn by his mother, Princess Diana: an 18-carat blue sapphire, set in white gold. (Getty photos)

  • Miley Cyrus & Liam Hemsworth

    In June 2012, <a href="" target="_hplink">19-year old Miley Cyrus was presented</a> with a 3.5-carat diamond engagement ring from boyfriend Liam Hemsworth. (Getty photo)

  • Anne Hathaway & Adam Shulman

    Adam Shulman presented the actress with a six-carat engagement ring in November 2011 which reportedly cost $150,000. (Pacific Coast News photo)

  • Keira Knightley & James Righton

    In May 2012, Keira Knightley became engaged to boyfriend James Righton, and was presented with a brilliant diamond on a platinum band. (Getty photo)

  • Sienna Miller & Jude Law

    When the couple got back together in 2010, Sienna Miller put her vintage engagement ring (originally given to her in 2005) back on. (Getty photos)

  • Angelina Jolie & Brad Pitt

    The couple officially announced their engagement in April 2012. Pitt designed an elegant ring with several (huge) diamonds. (Getty photos)

  • Jessica Biel & Justin Timberlake

    J-T proposed to Jessica Biel during the 2011 holidays, presenting the actress with a square-cut diamond costing $130,000. (Getty photos)

  • Miranda Kerr & Orlando Bloom

    As if this Aussie match could be any more perfect, Orlando Bloom gave the gorgeous Kerr an oval diamond reportedly worth $65,000 for their engagement in June 2010. (Getty photos)

  • Jennifer Garner & Ben Affleck

    When Ben Affleck got down on one knee in April 2004, he presented his now-baby mama Jennifer Garner a 4.5-carat diamond from Harry Winston. (Getty photos)

  • Gisele Bundchen & Tom Brady

    The Quarterback gave the supermodel a four-carat diamond when he proposed in 2009. (Getty photos)

  • Natalie Portman & Benjamin Millepied

    The actress became engaged to her "Black Swan" co-star in December 2010 and was given a round diamond surrounded by a circle of beautiful pavé diamonds. (Getty photos)

  • Rachel Bilson & Hayden Christensen

    The celebrity couple became engaged in 2008 and Bilson received a two-carat diamond worth $30,000. (Getty photos)

  • Halle Berry & Olivier Martinez

    The gorgeous actress accepted an emerald and gold Roberto Mazlo ring from boyfriend Olivier Martinez in March 2012. (Getty photos)

  • Jessica Simpson & Eric Johnson

    Jessica Simpson received a gorgeous $100,000 ruby-and-diamond Neil Lane ring from Eric Johnson in 2010. (Getty photos)

  • Kate Beckinsale & Len Wiseman

    The British beauty was proposed to by film director Len Wiseman in June 2003. She was given a horizontally set emerald-cut diamond by Neil Lane.

  • Carrie Underwood & Mike Fisher

    The country singer received a custom Johnathon Arndt ring from Mike Fisher in December 2009. (Getty photos)

  • Jennifer Hudson & David Otunga

    David Otunga proposed to the singer in September 2008 with a five-carat, Neil Lane engagement ring. (Getty photos)

  • Reese Witherspoon & Jim Toth

    The actress announced her engagement in December 2010 and showed off her four-carat ring. (Getty photos)

  • Kate Hudson & Matthew Bellamy

    Kate Hudson announced her engagement on the Today show in April 2011, showing off her $200,000 emerald-cut diamond. (Getty photos)

  • Drew Barrymore & Will Kopelman

    The couple announced their engagement in January 2012. Kopelman presented the actress with a four-carat diamond from Graff. (Getty photos)

  • Britney Spears & Jason Trawick

    Britney became engaged to Jason Trawick in December 2011, when he gave her a round diamond on a platinum band from Neil Lane. (Getty photos)

  • Katy Perry & Russell Brand

    In 2010, Katy Perry received a five-carat pink diamond engagement ring by Cartier by then boyfriend Russell Brand. Perry then exchanged the ring for a three-carat Golconda diamond from India. (Getty photos)

  • Jennifer Lopez & Marc Anthony

    Marc Anthony's engagement ring to J-Lo in 2004 was an 8.5-carat diamond, reportedly costing $4 million. (Getty photos)

  • Katie Holmes & Tom Cruise

    In 2005, Tom Cruise gave Katie Holmes a $250,000, five-carat, oval-cut solitaire set in rose gold. (Getty photos)

  • Heidi Klum & Seal

    The singer proposed to Heidi Klum in December 2004 with a gorgeous 8.5-carat diamond. (Getty photos)

  • Jennifer Lopez & Ben Affleck

    Before these two found new partners, J-Lo and Ben Affleck were engaged. Affleck presented the singer with a pink diamond, which Lopez showed off at the February 2003 premiere of 'Daredevil.' (Getty photos)

  • Michelle Williams & Heath Ledger

    Although their engagement wasn't highly publicized (and there is no information about William's engagement ring), it is clear that the stone that Ledger presented his baby-mama was huge, and quite pretty indeed. (Getty photos)

  • Emily Blunt & John Krasinski

    The couple announced their engagement in 2009, when Krasinski presented Blunt with a three-carat Neil Lane, Edwardian diamond set in platinum. (Getty photos)

  • Sarah Michelle Gellar & Freddie Prinze Jr.

    The couple announced their engagement in April 2001 and soon after Michelle Gellar was flashing her shiny, new ring. (Getty photos)

  • Scarlet Johansson & Ryan Reynolds

    Reynolds proposed to the gorge actress in 2008 and soon after Johansson was spotted with a shiny three-carat diamond, estimated at $30,000. (Getty photos)

  • Julia Roberts & Danny Moder

    Julia Roberts with given a simple but gorgeous engagement ring by Danny Morder shortly before their marriage in July 2002. (Getty photos)

  • Camila Alves & Matthew McConaughey

    The couple finally became engaged to longtime girlfriend (and mother to his now three children) in December 2011. (Getty photos)

  • Jessica Alba &

  • Top Ten Most Expensive Celebrity Engagement Rings

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