It was, quite literally, a diamond in the rough.

Appraised at $17,600, a 2.6-carat diamond ring with a platinum band discovered last week among donations at Goodwill’s distribution center at 627 N. Cameron St. in Harrisburg is the most expensive item ever given to Goodwill Industries Keystone Area, spokeswoman Jennifer Ross said.

It’s almost scary how easily the precious piece blended in with the no-longer-wanted gaudy gold, rhinestones, and cubic zirconia that flow through Goodwill’s thrift stores, Ross said.

“It could have ended up with a price tag of $5.99,” she said. “It makes me think about what treasures might be out there in some of our stores.”

The box it nested in “didn’t scream money,” Ross said.

But the filigree swirls on the band caught Barry Landis’ eye.

The retired jeweler from Camp Hill, who has sorted through Goodwill’s jewelry for the last two years, said he trembled while palming the slightly tarnished and dirty yet elegant 2-carat European diamond surrounded by 14 smaller diamonds.

Landis said 90 percent of the donated jewelry he sorts through is costume jewelry.

Was it an accidental donation? A relic of an ended marriage? A discarded family heirloom?

No one called missing a ring, Ross said.

“We can have fun thinking up stories behind it, but we just have no idea why it was donated,” Ross said.