In this article, we’ll tell you about such a hobby as meteorite hunting with a metal detector. When we discuss the topic of metal detectors, people tend to imagine detectorists digging the ground and looking for some ancient coins and relics. Very few of them know that with the help of metal detectors, you can go meteorite hunting as well. And the fact that meteorite pieces may cost much more than ancient coins very seldom pops into these people’s heads.
Most of those who decided to take up meteorite hunting as a hobby came to this idea by chance. Everyone knows that meteorite usually looks like an ordinary rock or a piece of iron.
Where do meteorites come from?
There is a large number of comets and asteroids flying around the Earth, and they are called meteoroids. Sometimes the latter get to the Earth’s orbit. Most of them burn in the atmosphere, but there are cases when they don’t burn completely and get to the Earth’s surface. Heavenly bodies that fell on the Earth’s surface are called meteorites.
Some explosions or appearance of craters don’t necessarily accompany the process of meteorites falling on the ground. Small rocks that weigh up to 1 kg fall at low speeds, and sometimes they even don’t get buried deep into the ground. Therefore, these can be detected both visually and using metal detectors.
What kind of meteorites are there?
Not all meteorites are metal ones. There are also silicaceous, carbonaceous, stony-iron, and metal meteorites. Most of the falling meteorites are rocks, while there is only 20% of iron or iron-stony one from them. More often meteorite fragments contain just plessite.
Stony meteorites are considered the cheapest ones. They are easy to find. When crashing into the Earth, they leave craters around this place. Things are much more complicated when talking about iron meteorites since their appearance is very much similar to a common rock.
Besides, their fragments easily melt, and it is not easy to detect them in the surrounding environment.
Heavenly bodies that contain peridot (a semiprecious metal) are of special interest to treasure hunters. That’s why to find such a valuable meteorite, you’ll need a very good metal detector.
How to look for meteorites with the help of a metal detector?
Almost all meteorites contain iron. Their type depends on the iron content. Iron and stony-iron ones are quite easy to detect using an ordinary metal detector. For example, it can be one of the devices described in this article.
I wouldn’t advise using very simple metal detectors, since their sensitivity is minimal and many meteorites are buried under a quite sick layer of ground. However, I wouldn’t recommend getting professional ones either, since you’ll have to work in quite clear areas and dig all the signals.
When selecting a metal detector for meteorite hunting, pay attention to the presence of All Metal mode, i.e., without discrimination function. Depending on the meteorite size and shape as well as nickel content in it, it can get into any discrimination segment of the device.
That’s why excluding any discrimination segment leads to missing some kinds of meteorites. The smaller it is, the closer to the end of the iron segment of discrimination scale it will appear. The smaller is meteorite size, the more challenging it is to find it. Not only because the signal is weaker, but also because it will appear lower on the discrimination scale.
Meteorite requires a lower discriminator setting than a piece of iron of the same size, since nickel contained in meteorites decreases the electric conductivity of the latter.
The reason why you should learn detecting small meteorites is that in the ground, there are much more small ones than large meteorites. Your chances to trip over a meteorite large as a football ball are quite small. It is more likely to find the one sized as a golf ball, and it is much more possible to find a meteorite of ping-pong ball size.
How can you tell a meteorite from a rock?
If you have already found something that resembles a meteorite, there are several signs with you can use to make sure that this is what you think it is.
Meteorites are divided into three main groups:
Iron meteorites are actually monolithic pieces of iron. Such a meteorite can consist both from pure iron and contain nickel or other metals as well. Stony-iron ones appear to look like a metal sponge with inclusions of minerals such as peridot, for example.
However, it is challenging to see between common rocks and stony meteorites. The latter have inclusions in the form of silicious balls and pieces of metal on their cleavage face.
Thus, the first sign that your find might be a meteorite is that gets magnetized, and you see a compass needle moving when it’s close to it. So, put a magnet to a rock that you’ve found. If it gets magnetized, it is likely to be a meteorite. Otherwise, it’s not, and this is some kind of sedimentary rock.
Of course, the more time it spends on the Earth’s surface and contacts with water, the more iron oxides you will see on it. By the way, this is a humid climate that is considered the main danger for meteorites. The oxidation process destroys them.
They will have some cavities that appeared due to high temperatures impact when meteorites fly through the atmosphere. However, quite often, it can have a smooth surface without any cavities or holes. But this is possible when a meteorite explodes at a high altitude, and small pieces fly in all directions like shrapnel. If these pieces rotate when they fly, they will have an irregular shape covered with cavities. But those that didn’t rotate have a bullet or cone shape quite often.
The flat side of such meteorites will have a sign of melting. On the cone part of its surface, it will have a fusion crust about several microns thick, while on its flat side, it will be up to 1 mm thick. You should keep in mind that meteorite can never burn to the whole and have a completely porous structure.
More often than not, meteorites are confused with metallurgy waste called slag. It has signs of flowing, and it is heavy with shining metal inclusions. The meteorite will never have a porous structure. If you find something like this, it is more likely to be a slag that is definitely of terrestrial origin, or it can be some iron and steel founding waste.
Another important thing is that meteorite always has a higher density than any other subsurface rock. It is heavy. Even if you compare granite and meteorite of similar volume, the latter will be significantly heavier. If the summation of signs is enough, you can state that you’ve found a heavenly body.
The information mentioned above is quite enough to make sure that you won’t take all the rocks around into your house.
Where to look for meteorites?
They fall very often in many corners of the world. More often, meteorites are found in large and open spaces. Meteorite fragments are often detected in fields and semi savannas. I wouldn’t recommend going around thickly planted areas since thick grass and trees will get in the way.
You should find some uninhabited place where meteorites could have accumulated for thousands of years without getting covered with dirt and various rubbish and without getting dissolved in water. The dry climate also allows meteorites to stay undamaged for a long time before they start to corrode and turn into dust.
The place shouldn’t be trashy or have ‘hot rocks’ around that will affect a metal detector performance. Because, if you stop and dig these each time, you won’t be able to go through a large area.