Millennium Star

{{Short description|203.04-carat colourless diamond from Zaire}}

{{Use dmy dates|date=September 2020}}

{{more citations needed|date=September 2008}}

{{Infobox diamond

| name = Millennium Star

| image =

| caption =

| weight = {{convert|203.04|carat|g|abbr=on}}

| color = Grade D Colorless

| cut = Pear Brilliant

| country = Zaire

| mine = Mbuji-Mayi

| found = 1990

| cutter = Steinmetz Group

| original_owner =

| owner = De Beers

| value = Insured for £100,000,000

}}

The Millennium Star is a diamond that was sold to an anonymous buyer in 2006, thought to be in Asia, by De Beers. At 203.04 carats (40.608 g), it is the world's second-largest known top-color (grade D, i.e., colorless), internally and externally flawless, pear-shaped diamond.

The diamond was discovered in the Mbuji-Mayi district of Zaire in 1990 in alluvial deposits; uncut, it was 777 carats (155.4  g). De Beers purchased it during the height of the country's Civil War in the early to mid-nineties. Workers of the Steinmetz Diamond Group took over three years to produce the classic pear form. The cutting was done using lasers.

It was first displayed in October 1999 as the centerpiece of the De Beers Millennium diamond collection. The collection also includes eleven blue diamonds totaling 118 carats (23.6 g) and The Heart of Eternity. They were displayed at London's Millennium Dome over 2000. There was an attempt on 7 November 2000 to steal the collection (see Millennium Dome raid), but the Metropolitan Police discovered the plot and arrested the robbers before their escape.{{cite news| url=http://news.bbc.co.uk/1/hi/uk/1010974.stm |work=BBC News | title=Great Dome robbery foiled | date=7 November 2000 | accessdate=12 May 2010}} Crime journalist Kris Hollington wrote a book called Diamond Geezers ({{ISBN|1843171228}}) about the attempted theft. The book also features a detailed history of the Millennium Star.

In 2025 the Millennium Star was featured in the Netflix documentary The Diamond Heist, which recounts the attempted theft of the diamond during the Millennium Dome raid in 2000. The film directed by Guy Ritchie, details how the gem was targeted in one of the most ambitious heist attempts in British history.{{cite news| url=https://www.theguardian.com/tv-and-radio/2025/apr/16/the-diamond-heist-review-guy-ritchie-millennium-dome-jewel-robbery-netflix | date=16 April 2025 | accessdate=20 April 2025 | title=The Diamond Heist review – Guy Ritchie's thrilling tale of the failed Millennium Dome jewel robbery | work=The Guardian | last1=Mangan | first1=Lucy }} It was orchestrated by a gang that planned to smash their way into the exhibit with Lee Wenham being the mastermind of the operation. The documentary highlights the elaborate security measures and the dramatic police sting operation that ultimately foiled the plot.

The largest cut white (D) diamond by weight is the 1991 modified heart-shaped {{convert|273.85|carat|g}} Centenary Diamond.