The rock might not look like anything special, but in fact it's a fragment of the Muonionalusta, an iron meteorite believed to be the oldest in the world.
It hit the border between Sweden and Finland more than one million years ago, and to date only around 40 pieces have been found. A fragment described by specialist auction site Catawiki's experts as "exceptionally large" and weighing 26.5 kilograms is up for sale with bidding open until Sunday.
The name comes from the Muonio River in northern Sweden and Finland, close to the spot where the meteorite was first discovered in 1910. It had been there for between 800,000 and one million years, but the rock's actual age is estimated at 4.5 billion years.
According to Catawiki, which is hosting the auction, the meteorite is expected to fetch up to around 200,000 kronor. This includes the rock itself and a certificate guaranteeing its authenticity.