Occasionally, our house regurgitates something that one of us have found and brought home. Yesterday, it unearthed this object that my wife found whilst we were ‘out and about’ once. We can’t remember where she found it but it could have been a beach. It’s a heavy ‘metallic’ pebble type object – it feels too heavy to be made of stone. It is very hard, it is not magnetic (or if it is, it’s very subtly so – a fridge magnet doesn’t stick to it) and it’s mainly black in appearance, mottled with red and grey and has an irregular smooth appearance and feel. It looks like it was once malleable, or molten.
Our first reaction was that it might be a meteorite. After a fair chunk of research on that there internet, I’d now say it looks more like a meteorwrong than a meteorite. Some of the ‘expert’ sites out there suggest that if it is weighted like metal and it is not magnetic then it’s unlikely to be a meteorite. However, it’s form is quite meteoric, indeed due to it’s close match to the formation known as Regmaglypts – small indentations that look like the sort of thumb prints you get in Plasticine.
Partially fueled by really wanting this to be a meteorite, I plodded on with my research. Every question I had answered, opened up another question, however, there was a strong indication that it might be a Hematite. “But why doesn’t it appear to be magnetic?” (thought I). Wikipedia said (deep breath..) “Hematite is an antiferromagnetic material below the Morin transition at 250 K, and a canted antiferromagnet or weakly ferromagnetic above the Morin transition and below its Néel temperature at 948 K, above which it is paramagnetic.” …which left me non the wiser really. I think I need that translated – does that mean it won’t stick to my fridge magnet? (I know just the man to ask.. )
A fairly conclusive sounding test called ‘The Streak Test’ proved to be quite meteorite damning though. The Streak Test involves vigorously rubbing the object on the back of a ceramic tile (none to hand, the inside lid of toilet sufficed). According to the University of New Mexico’s Department of Earth and Planetary Sciences “If it leaves a black gray streak the sample is almost certainly magnetite, and if it leaves a red-brown streak it is almost certainly hematite. A meteorite, unless it is very heavily weathered, will not leave a streak on the tile.” Our little fella left a distinctly red-brown streak, therefore it is almost certainly hematite.
Bit of a shame, but on the plus side, I now know a lot more about meteorites than I did and, eyes down as well as up, I’ll be looking out for them. If I can ever find one that looks like the Esquel Pallasite meteorite as pictured below, I’ll be a happy man.