The New York Times notes in history:
The then and now Mrs C.V. Whitney, Mary Lou Hosford, was robbed of $780 000 worth of Whitney jewels, heirlooms for the most part.
Emeralds, turquoise and diamond necklaces and sapphires and rubies.
It was the biggest crime story ever to hit Saratoga.
I hope she didn’t lose her wonderful and amazing wild roses tiara, which she wore on opening the Metropolitan Opera in NY.
It was not the ruby bandeau, of the Empress Sissi (which I had on the picture to compare).
It was similar but not the same, it looks like more the earlier sketch made by Jeweler Köchert, see on top.
The daughter-in-law of Gertrude Vanderbilt Payne Whitney, sister of Gladys Moore Vanderbilt (1886–1965), who married Count László Széchenyi (1879–1938), which had very good connections to the imperial court of Vienna, so it could be absolutely true, it had an imperial history.