It's been a banner year for tiny West African nation of Sierra Leone. The recent discovery of the 476.7-carat "Meya Prosperity" — which followed the March discovery of the even more massive 709.1-carat "Peace Diamond" — gives Sierra Leone the distinction of being the source of the world's two biggest diamond finds of 2017.

The yellow-hued Peace Diamond is believed to be the 14th largest diamond ever discovered, and the colorless Meya Prosperity is being slotted at #29.

The Peace Diamond, which was pulled from a river bed by pastor Emmanuel Momoh, is scheduled to be sold at a New York auction on December 4. Some experts believe the diamond could yield as much as $50 million.

Meya Prosperity will also be sold at international auction, but it's not clear if it will go under the hammer with the Peace Diamond in New York.

In the wild world of fabulously large diamonds, the diminutive Sierra Leone can be considered a powerhouse.

In 1972, the 968.9-carat "Star of Sierra Leone" diamond was discovered by miners in the Koidu area of eastern Sierra Leone. The gem was eventually cut into 17 separate finished diamonds, of which 13 were deemed to be flawless. The Star of Sierra Leone ranks as the fourth-largest gem-quality diamond and the largest alluvial diamond ever discovered.

In 1945, the 770-carat Woyie River Diamond was also found near Koidu. Ranked the 9th-largest diamond ever discovered, the D-flawless rough was cut into 30 gems, including 10 weighing more than 20 carats each. The rough gem earned star status when it was brought to London and viewed by Queen Mary in October 1947.

The 476.7-carat Meya Prosperity is named for Meya Mining, which discovered the stone and maintains an exclusive license to explore a concession spanning 80 square miles of the diamond-rich Kono District. The mining company also noted that two other sizable diamonds — one weighing 19.70 carats and the other weighing 27.93 carats — were discovered only a few hours after unearthing the Meya Prosperity.

"[The latest find] provides a remarkable indication of the potential of the mineral resources in the area," Sahr Wonday, director general of Sierra Leone's National Minerals Agency, told news24.com.

Credit: Photos courtesy of Trustco Resources. Map by Google Maps.