Is it a Meteorite?

While you and I may not have the funds to spend six months on an Antarctic expedition to collect meteorites, all is not lost, for meteorites are found all over the world, with some 20 recorded falls in the UK over the last few hundred years. But how can you tell if you’ve picked up a piece of the early Solar System’s history, or just a common garden rock? If you can answer yes to these questions you could have a national treasure in your hands:

Is it attracted by a magnet?

Meteorites have a high iron content so they will often attract a magnet. However, there are a lot of Earth rocks that are magnetic too, so you will need to answer some more questions to confirm your discovery.

Does it have a fusion crust?

When a meteorite careers through Earth's atmosphere it burns, forming a dark brown or black ‘fusion crust’. If the rock is cracked open you will clearly see the thin veneer of the fusion crust against a pale interior. You might also see thin, wavy lines on the crust. These are flow lines caused by the surface having melted and flowed around the rock.

Is it heavy for its size?

Because of their high iron content meteorites are quite heavy compared with Earth rocks of the same size.

Does it have rounded corners?

Although meteorites are irregular in shape they will often have rounded corners, smoothed as they melted during their journey through the atmosphere. If a large flat surface is exposed, the other half of the rock may only be a stone’s throw away (literally).

Does it have regmaglypts?

Regmaglypts, more commonly referred to as ‘thumb-prints’, are indentations in the meteorites’ surface that look like a thumb has been pressed into a malleable material. While meteorites generally don’t have holes, this thumbprint texture is often seen.

Does it contain chondrules?

If there are small round features inside the rock, which are sometimes exposed on the surface too, these might be chondrules. These spherical grains formed in the solar disc some 4.5 billion years ago and accreted to form the first rocky bodies in the Solar System and, ultimately, the planets.

Do you still think your rock might be a meteorite?

In the UK you can take it along to the Angela Marmont Centre at the Natural History Museum in London where it will pass through their enquiry service for further examination.