Tabular icebergs form, she said, through a process that's a bit like a fingernail growing too long and cracking off at the end. They're often rectangular and geometric as a result, she added.

"What makes this one a bit unusual is that it looks almost like a square," Brunt said.

It's difficult to tell the size of the iceberg in this photo, she said, but it's likely more than a mile across. And, as with all icebergs, the part visible above the surface is just the top 10 percent of its mass. The rest, Brunt said, is hidden underwater.

In the case of tabular icebergs, she said, that subsurface mass is usually regular-looking and geometric, similar to what's visible above. This iceberg looks pretty fresh, she said — its sharp corners indicate that wind and waves haven't had much time to break it down.

But despite the berg's large mass, Brunt said, she wouldn't advise going on a walk on its surface.

"It probably wouldn't flip over," she said.

The thing is still much wider than it is deep, after all. But it's small enough to be unstable and crack up at any moment.

So, it's probably best to marvel at the thing from a distance.