While digging up their backyard last week, looking for worms to take on an upcoming fishing trip, two Kitchener sisters stumbled upon something much larger – and much more curious.

Deep in the ground behind their Kitchener home, they found something transparent and shiny, with a bluish hue.

It’s as big as their heads, and it looks like it may have once been part of something much bigger.

But what is it?

Ali Hiuser’s first thought was that it was space junk – part of the meteorite believed to have fallen in the St. Thomas area last month, perhaps.

That seems unlikely, according to those leading the search for the meteorite.

“It should have a … darker outer surface,” says Phil McCausland, a professor in Western University’s earth sciences department.

Meteorite debris would also likely be on or just barely into the ground, while what the Hiuser sisters found was found farther down.

“It was really buried. Only the tiny tip of it was showing. We thought there was more, so we started to dig,” the 11-year-old says.

The sisters have found items buried in their backyard before, including plaques and old newspapers, but never anything quite so curious.

Gary Winkler, a retired teacher and member of the KW Gem and Mineral Club, was brought in to examine the item.

He’s not sure what it is, but says it’s not glass, quartz, a diamond or ruby.

“It’s very pretty. I’ve never seen anything so big and blue and shiny,” he says.

Whatever it is, Winkler believes it didn’t occur naturally and was placed in the backyard – although he’s unsure when or by whom.

“It seems out of place,” he says.

“Minerals usually occur in deposits, not in somebody’s backyard.”

Hiuser and her sister plan to keep the item in their home – at least, unless it turns out to be valuable.

“If it costs like a million dollars or something, we would probably sell it,” says Hiuser.

The item will be sent to the University of Waterloo for further testing.