Previously undiscovered photo of undocumented Russian Crown Jewels was recently discovered in the USGS library. The photo appears in a 1922 album called “Russian Diamond Fund,” that was uncovered in the rare book room of the library. This necklace was one of the four undocumented jewels. Credit: U.S. Geological Survey Department of the Interior/USGS U.S. Geological Survey

Leave it up to an unassuming American government agency to point out a hole in Russia’s crown jewel collection.

Last month the U.S. Geological Survey — the scientific bureau charged with the classification and examination of America’s mineral resources and whatnot — announced it had found four pieces missing from Ivan’s bling vault. Well, the U.S.G.S. didn’t actually find the missing jewelery, it just pointed out that the pieces once existed and may now be gone.

Were they swiped? Or were they hoked almost 90 years ago to fund the emerging Communist revolution? Are they even missing?

No one knows for sure. The true story behind the stones remains a mystery.

Here’s the rundown on what we do know. Sometime in the 1920s, a U.S.G.S. employee named George Kunz acquired a catalog of photos of Russia’s royal treasures entitled “Russian Diamond Fund” during his travels overseas. After Kunz died in 1934, the tome, which had a publication date of 1922, made its way to the U.S.G.S. library and right away got to work gathering dust. Also gathering dust in the library was a copy of “Russia’s Treasure of Diamonds and Precious Stones,” a 1925 work along the same lines.

Both books are allegedly inventories of the country’s royal jewels, worn by the Romanov family from the 1600s until 1917 when their reign came to an end amid the revolution (Tsar Nicholas II and the last of the royals were executed in 1918, for those keeping track).

Fast forward to the present day when U.S.G.S officials got around to blowing off the dust and comparing the books. Inside “Russian Diamond Fund” they found four items not listed in “Russia’s Treasure.” These include:

— A sapphire and diamond tiara — A sapphire bracelet — An emerald necklace (pictured above) — A sapphire brooch in the shape of a bow

“This 1922 album contains photographs that document the Imperial Crown Jewels and augments the official 1925 catalog with images of pieces that were not previously known to exist,” U.S.G.S. Library Director Richard Huffine said in a prepared statement.

After the Tsar was overthrown, the new Russian government held the jewels in secret until the Red Army versus White Army bloodshed began winding down in 1922. That’s when they were unpacked, and the Diamond Fund photos appear to part of an initial inventory of the stones, and some of the pictures from that work appear to have been used in the Russia’s Treasures book, U.S.G.S. officials said.

Researchers investigating the additional pieces listed in the earlier book determined that the brooch was sold in London in 1927. It wasn’t immediately clear who bought it, who sold it or what it went for. The fate of the other three jewels is unknown.

In addition to the U.S.G.S. librarians, others involved in the research included the Hillwood Museum and the Smithsonian Institution in Washington, D.C., and the Gemological Institute of America in Carlsbad, Calif.

Below is a U.S.G.S. video about the case, and photos of the other missing pieces are at the U.S.G.S. website.

So, check your jewelry boxes and keep an eye out when browsing garage sales and second-hand stores. You never know where these might end up. Also, dust off your old book collection. In 2007, a copy of “Russia’s Treasure of Diamonds and Precious Stones” sold on auction at Christie’s for $141,984.