A rare crimson red diamond unveiled at Smithsonian Natural History Museumbr br A brilliant red diamond, one of the rarest gemstones on Earth was unveiled on Tuesday, April 1, — the newest addition to the gem collection at the Smithsonian's National Museum of Natural History.br br The 2.33 carat scarlet stunner is part of the Winston Red Diamond and Winston Fancy Color Diamond Collection. The showpiece of the collection, the ruby-colored jewel is considered a one in 25 million sort of a find.br br The collection was presented to the Smithsonian by Ronald Winston, the son of famed jeweler Harry Winston. The new exhibit is located in the same room as another rare gem shared with the museum by the Winston family — the Hope Diamond.