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London Museum to Put 9,381-Carat Blue Topaz on Display
On long-term loan from the family who discovered it in Brazil, “The Ostro Stone” will be available for public viewing at the Natural History Museum starting Oct. 19.

London--The U.K. will present a unique opportunity for gemstone lovers beginning next month as a flawless, faceted blue topaz, thought to be the largest of its kind, goes on display.
Starting Oct. 19, a 9,381-carat blue topaz called “The Ostro Stone” will go on permanent display to the public in the London Natural History Museum’s Minerals gallery.
British gemstone pioneer and explorer Max Ostro discovered the stone in its natural form in 1960 in Minas Gerais, Brazil, and the topaz has been in the family vault ever since. It is being put on display now through a long-term loan from his son, Maurice Ostro, chairman of Ostro Minerals.
It’s approximately 6 inches in length and 4 inches wide, with its deep blue color resulting from a treatment applied when it was in its rough state.
The museum said it’s the first large cut topaz of its kind to go on display there, showing alongside other important specimens from its mineral collections. It did not disclose the value of the stone.
The Ostro Stone will be unveiled at a private launch event in the Museum’s Hintze Hall on Oct. 6, with performances from fashion designer Daphne Guinness and music producer Tony Visconti.
Three new pieces of “wearable art” featuring topaz donated by Ostro and designed by contemporary artists Isaac Julien, Nicole Wermers and Catherine Yass also will be unveiled.
Though at the start of his career in the gemstone world Max Ostro was responsible for introducing a number of gems from South America to the colored stone industry in the Far East, he was long enthralled with blue topaz in particular, working closely with it until his death in 2010.
He has been credited with helping the gem reach the popularity it has to day, and the terms London blue and Swiss blue also are associated with the Ostro family.
Mike Rumsey, senior curator of the museum’s Minerals Collection, said, “This stone is an excellent example of how as humans, we have crafted beautiful and desirable objects from the natural mineral specimens we find around us, like those that we preserve in the collections at the museum. It will be on display alongside some of our world leading collection of minerals and gems, which is studied by scientists here to find new sources of minerals, gemstones and metals.”
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