The fantastic 18.96 carats rectangular "The Pink Legacy" diamond will be on display in Hong Kong from Sept. 28 to 30 for interested Chinese buyers to appreciate before being sold at auction on Nov. 13 at Christie's Magnificent Jewels Sale in Geneva, Switzerland.

Hong Kong was selected as the first stop for The Pink Legacy's world tour for a good reason: the world's most expensive gem, another pink diamond, was sold at an auction in Hong Kong in 2017.

After Hong Kong, The Pink Legacy will be shown in London from Oct. 4-7 and Oct. 12-15; New York from Nov. 2-5 and at the Four Seasons Hotel des Bergues, Geneva from Nov. 9-13.

This fabulous gem, which is one of only a few pink diamonds in the world, is expected to fetch a near-record price of $50 million when it goes under the hammer. If it does sell for $50 million, this exquisite gem will be the third most expensive diamond sold at an auction in history.

Pink diamonds are the most expensive diamonds sold at auctions worldwide. Five of the top 10 most expensive diamonds ever sold are pink diamonds, including the most expensive, "The Pink Star," an oval-shaped 59.6-carat pink diamond sold at Sotheby's Hong Kong for $71 million in April 2017.

The other pink diamonds in the top 10 list are The Graff Vivid Pink Diamond (Price: $46 million); The Prince Pink Diamond. (Price: $39.3 million); The Sweet Josephine Pink Diamond (Price: $28.5 million) and The Perfect Pink Diamond (Price: $23.8 million).

 The Pink Star is the largest known diamond to be awarded a Vivid Pink color grade. The Pink Legacy has also received a Vivid Pink color grade. The Gemological Institute of America awarded "The Pink Legacy" its highest diamond color designation, "vivid," meaning the stone is saturated and displays the optimum hue.

The Pink Legacy is also graded internally as very pure. This is extremely rare since the pink color is formed by pressure and slippage of the crystal lattice. The process typically causes imperfections in the stone, said Christie's.

Pink diamonds of any size and depth of color have always had a special allure even among knowledgeable industry members, said Tom Moses, executive vice president at Gemological Institute of America. Moses said the 18.96-carat emerald cut pink diamond is among the rarest of all gemstones.

The discovery of The Pink Legacy, a previously unrecorded and remarkable diamond, will cause immense excitement with collectors and connoisseurs of diamonds around the world, said Rahul Kadakia, international head of jewelry for Christie's.

The second most expensive diamond ever sold is the Oppenheimer Blue diamond, which sold for $57.2 million in 2016.