The Earring of Madame…X

A former sergeant in the New York Police Department needs your help to solve a St. Patrick’s Day mystery — The Case of the Lost Earring.

And this isn’t just any earring. For while it surely has sentimental value to its unknown owner, it appears to possess real monetary value, too.

“It’s 18-carat gold,” said Robin Sternberg, a 20-year NYPD veteran who retired in 2005. “Most likely it’s a blue topaz stone, but it could possibly be an aquamarine beryl.”

Now the average cop doesn’t typically have such an intimate familiarly with precious gemstones. But Sternberg is not your average cop:

She’s a geology-and-astronomy buff who adores science, works as a lab instructor teaching forensic biology at Hunter College, doubles as a veterinary nurse providing home health care for dogs and cats, and, in her spare time, takes philosophy courses at Hunter in pursuit of her second undergraduate degree.

Oh, and she’s also a trained artist who got her first degree from the School of Visual Arts in 1985, the same year she was sworn in as a transit police officer in Brooklyn.

“I didn’t really want to be an artist,” Sternberg explains. “I wanted to be Nancy Drew.”

And like that culturally iconic fictional female sleuth — who is also said to have inspired such New Yorkers as Beverly Sills, Barbara Walters, Sonia Sotomayor and Hillary Clinton — Sternberg is driven by the hunt for clues, the solving of mysteries and the closing of tough cases.

Her latest seems pretty daunting. It began at around 4 p.m. on March 17, on the west side of Second Avenue between 85th and 86th Streets, in the spillover that traditionally follows the St. Patrick’s Day Parade.

East Siders have long dubbed this assemblage the “parade after the parade.” While the official line of march ends on Fifth Avenue at 79th Street, the festivities have always jumped across Madison and Park Avenues and mostly bypassed Lexington and Third Avenues to resume, with abandon, on the swath of Second Avenue between 79th and 86th Streets.

This unofficial post-parade hub, at least metaphorically, is awash in green.

The throngs include thousands of Hibernians, tourists, soldiers, sailors, hardhats, teachers, steamfitters, politicians, Con Ed workers, transit workers who still call the IRT the “Irish Republican Transit,” veterans of the New York National Guard’s “Fighting 69th” Infantry Battalion, the Irish Wolfhounds that are the mascot of the 69th, assorted New Yorkers of all stripes, and of course, the bagpipe-and-drum brigades of the NYPD and FDNY Emerald Societies.

Anyone of them, it seems, except the wolfhounds, could have lost that earring amid the hubbub.

Lured by the open-door saloons that have beckoned for generations, the revelers piled into Brady’s Bar on 82nd Street, which has been owned and operated by the same Irish family since 1961, and the Heidelberg just south of 86th Street, a relic from the 1930s when the street was widely known as the “German Broadway” or “Sauerkraut Boulevard.”

They also stood wall to wall at one of the newcomers to the avenue, the three-year-old Supply House, between 85th and 86th Streets, which has quickly blended into the old Yorkville street scene.

It was there on the sidewalk, directly in front of the bar, that Sternberg, a 25-year resident of the Upper East Side, looked down and saw a small flash of prismatic light.

“I often walk with my head down,” she said. “I always find pennies, and I always bend down and pick them up, so now I’ve got piggy banks filled with pennies!”

The sparkling, shimmering object lying on a small blanket of snow was no penny. It was a lone and exceptionally beautifully pendant earring.

Thus began her search for the owner. She ventured into the Supply House, hoping to find her at the bar. Packed to the gills, it was all but impenetrable. She dropped by again the next day, and the publican immediately agreed to post fliers in his establishment in case the woman returned.

“We’re all for helping out pretty much everyone in the neighborhood we can,” said Ryan O’Flaherty, an owner and manager of the saloon. “Isn’t that what most nice people would do? We’ll do our bit in any way we can, and hopefully, we’ll get the earring back to its rightful owner.”

Of course, there was no guarantee that she was a Supply House patron, and so Sternberg photographed the earring and taped multiple fliers to all the lampposts on a two-block stretch of Second Avenue between 84th and 86th Streets. Inevitably, some have already been torn down; others are still standing.

“I will happily return the earring to you,” they proclaim, “IF you can show me the matching earring!”

What motivated her? Sternberg — who became an NYPD sergeant in 1994, after making detective in 1989 as the only woman in her class of 10 trainees — cherishes the jewelry her boyfriend has given her, and she says she would be heart-struck if it ever went missing.

“If I had an earring that was that beautiful, and somehow I’d lost it, and I was sentimental, I’d be absolutely devastated,” she said. “And I would really, really, really want to get it back. So I thought, ‘Let me try everything I can to get this back to its owner.’”

And what if no one comes forward now to claim the gem? Well, Sternberg is prepared for that, too.

“If I can’t find the owner now, I’ll keep it for another year,” she said. “Then, come next St. Patrick’s Day, I’ll put up some more fliers. Because one can’t really know, but maybe this is something the owner does once a year. And if she doesn’t see it this year, then maybe she’ll see it next year.”

Did you lose this earring? Do you know who did? Can you help Robin Sternberg solve The Case of the Lost Earring and return it to its rightful owner? Let us know.

Contact reporter Douglas Feiden, invreporter@strausnews.com. You can also get in touch with the staff of the Supply House, at 1647 Second Avenue, between 85th and 86th Streets, 646-861-3585.