If you close your eyes and picture an iceberg, the chances are you’ll picture something cold and white, floating on the sea.

Most likely it’ll be quite large, and if you’re really imaginative, it could have a polar bear floating on it.

But it’s very unlikely that the iceberg you picture will look anything like the one that was recently spotted by a shrimp fisherman off the coast of Labrador recently.

That’s because the iceberg spotted by Faroe Islander Hallur Antoniussen was not white, but black.

According to Antoniussen, the iceberg looked nothing like anything he’d ever seen before – and at a total of 47 icebergs spotted just the previous day, and fifty years as a fisherman, he has a good knowledge of the icy formations.

Instead, the berg had an unusual shape, and he suggested in a CBC interview that it was three times the size of a bungalow:

“I have seen icebergs that are rolled, what they say have rolled in the beach with some rocks in it. This one here is completely different. It’s not only that he is all black. He is almost in a diamond shape.”

And while some commenters suggested that the iceberg may contain large amounts of oil, there are other reasons why it could be such an unusual icy shade.

According to Memorial University’s Lev Tarasov, the iceberg could contain large amounts of volcanic ash.

As Tarasov told CBC, the iceberg is likely at least 1,000 years old, but it could be up to 100,000 years of age – and with this in mind, it could reveal the history of an ancient volcano, or an early meteor strike.

However, as Tarasov hastened to add, this unusual iceberg will only tell a small part of the story, since most of the iceberg – melted or broken away from a bigger ice sheet – is actually below the water line:

“Over time, as it travels around Baffin Bay and down the coast of Labrador, it’s melting away. So I think a lot of that ice is melted away. Maybe the part that’s clean is underneath, right? Again, 90 per cent of the ice is underneath the water. So we’re only seeing the tip of the iceberg on top.”

Whatever the explanation, this is a fascinating display of the diversity of nature, and a reminder that even though we think we know at lot about the world, it still has many secrets yet to unveil.

Thought that was fascinating? Here’s another story you might like: Why You’ll Never See A Great White Shark In An Aquarium