Do you think you found a meteorite?
Many people have been in the desert, along the riverbank, or even in their own backyard and found an unusual rock. Some of these rocks are believed to bemeteorites. But how do we know? A good starting point is useful information andTests to identify meteoritesWhat can you do to answer your question "Is it a meteorite?"
Meteors come in three different main classes, stony, ferrous, and ferrous meteorites. But to be honest, there are many more royal types within the three classes, so it can be difficult to make an accurate classification. But for our purpose here we are going to work with the three main classes.
stone meteorites
This is by far the largest of the three main types. These meteorites look like rocks because they are composed mostly of mineral material, similar to many rocks that form here on Earth. But real meteorites are usually much heavier than terrestrial rocks for their size. So "heavy for size" is the first thing to look for in your suspect stone.
If the stone breaks, it will be solid inside. It will not be porous like lava rock. It may have small round ball-like structures visible on the fractured surface. these are calledchondrulesand many stony meteorites (chondrites) will have them. But it won't have holes if it's a meteorite. Most stony meteorites do not contain bright crystals. They do not have layers or bands with different striations of mineral types. So "solid", "non-crystalline" and "non-layered" are phrases to remember.
Stony meteorites often contain nickel-iron grains. Metallic iron in the rocks of the earth is very rare. Earth's humid atmosphere long ago converted nearly all native iron to another chemical form of iron. So if you grind down a small dot on your suspected rock and find shiny, shiny metal dots, that's another good indication that you might have a rock-type meteorite. One thing to think about here is what I mean by shiny metal dots. These will not have any metallic shine or shine. The metal flecks in meteorites are actual metal; They will look like the chrome of a car. So having metal grain is next on our list of features.
Since meteorites often contain iron, they react when a strong magnet is brought close to them. If a magnet sticks to your stone, or a magnet pulls on the stone when it is dangling from a string, it could mean that there is ferrous metal in the suspect stone. You should sand down a small spot like the one above and see if there is any metal. But many rocks on Earth that are not meteorites contain iron in chemical forms sensitive to magnets. Magnetite is one of the most common and is often found in rocks. It sticks to magnets. But it will have no metal grains when it is ground, and the powder produced by grinding will be black. The dust produced by grinding most meteorites is brown. Fresh meteorites may not produce a brown dust, but older stony meteorites often do. "Responds to a magnet" and makes a "brown or dusty streak" is the next feature.
Meteors first pass through Earth's atmosphere at the same speed as in space. This speed is thousands of kilometers per hour. They interact with the thin air above the ground and melt at the outer surface. This molten lining is called "melt crust." It is often black when the meteorite has recently fallen, but gradually turns brown over time when it is on the ground. Iron grains and minerals oxidize and weathering causes the meteorite to turn brown. So black or brown on the outside is the feature we're discussing now, but it might be the first thing to look for in rocks.
If your rock has some of the properties, but not all of them, it may be some type of rocky meteorite. Some stone meteorites don't have much metal or metal in them, so nothing will appear when you crush them, and they don't respond very strongly to a magnet. You only have your outward appearance to guide you. If you think it has melt scale and appears to have flight marks from traveling through the atmosphere while melting outside, send it in for investigation.
iron meteorites
Meteors that consist almost exclusively of nickel-iron are much rarer to find. These meteorites are black or brown on the outside. They will be very heavy and a magnet will stick to them strongly since they are metal. When you sand or grind them, they show metal like any piece of iron in your garage or a rusty junkyard.
The iron meteorite and meteorites in general can have almost any shape. They have rounded corners, but they do not have to be spherical. Iron meteorites and other types can be characterized by indentations on the outer surface. These are commonly known as fingerprints. I use that name instead of the scientific term "regmaglyphs" because the fingerprints describe them so well. Imagine pressing your thumb into the pottery clay many times. These are the kinds of marks that meteorites sometimes have on their outer surface. Remember that they are not porous. They won't have holes, but they may have these indentations on the surface.
Iron meteorites can easily be mistaken for rusty pieces of artificial iron and steel. Old mill balls and cannonballs, after many years of oxidation, are good mimics of meteorites. Like airplane and car parts, motorcycle parts are now found in the desert and other remote areas. It is often necessary to test for the presence of nickel to determine for sure if a piece of iron is a meteorite. All iron meteorites contain both nickel and iron. This test is tricky enough to make it something a first-time stone finder probably isn't. But send the stone to a testing facility for analysis. Or if you can remove a piece, send it in its place. A piece the size of a walnut is enough to make up your mind. If it is a meteorite, it must also meet the requirements for official classification and inclusion in the meteorite catalogue. The locator must file a locator report with the Meteoritical Society, whose online address can be found below. Twenty grams of a meteor or 20% of a small meteor are donated to meet the requirement. This value is placed in a permanent collection that scientists can access once the analysis is complete.
the feldspar meteorite
These are the last major types of meteorites. As their name suggests, they share characteristics of the two previous types. They are made of a mixture of nickel-iron and stone. It will be possible to sand or grind and find a lot of metal. But often it will be possible to find points on the surface where an ordinary file is useless, since the material is mineral. The mineral content may be dark silicate minerals or yellowish-green or yellowish-brown crystals of olivine.
Ironstone meteorites are heavy because they contain a lot of iron. For the same reason, they are usually very oxidized. And the olivine crystals may have been discolored on the outside or may have fallen off as a result of oxidation and erosion processes. Furnace slag is sometimes confused with stony iron meteorite material because it often contains residual iron along with the molten rock component. But blast furnace slag is generally porous and meteorites are not.
Is it a meteorite?
Now, for about a hundred bucks, you can find out. A Colorado company called Geo Labs makes it easy to analyze your rock with theirs.Meteor Identification Service. They offer XRF services specifically designed for meteorite identification. They require that all samples be submitted with a sample submission form and that the samples adhere to their strict submission guidelines. They use state-of-the-art X-ray fluorescence technology to determine the elemental composition of a sample, and can typically provide a quick yes or no answer to that burning question, in about a week: Is it a meteorite?
How to identify a meteorite
Not a day goes by that we don't get emails from people who think they've done this.i found a meteorite. In this sense we have a chapter in our new book"Meteors: how to recognize visitors from space" Onehow to recognize meteorites. Below is the chapter of our new eBook.
Meteorite or evil meteorite
Der Side-by-Side-Test
Meteor hunters have come up with a fun term to refer to all rocks that look like meteors but aren't, they call them meteor "bugs."
A meteorite testing laboratory said a few years ago that it receives an average of 7,000 rock samples a year from people who thought they had found a meteorite. On average, there were only one or two true meteorites a year. Given the wonderful media attention that meteorite hunting has received in the last three or four years, this facility had to stop accepting samples because it could no longer handle the demand. It is hoped that with the help of this book and its photographs, the number of real meteorites sent to laboratories will be greatly increased.
There is nothing better than a step by step tutorial to learn new things. Here is a test with two stones that look very similar. One is a meteorite and the other is not. Much more will be said later about the features that can be seen in the photos.
The two stones shown above are approximately the same color and size. Both are the right color for a possible meteorite. Both are forms that a stony meteorite could very well take. The texture on the surface is in the range that a meteorite can have. The stone on the left weighs 9 grams and the one on the right 6.9 grams.
Both stones have a magnet. Therefore, both are somehow related to iron in their composition. The next step in testing, whether at home or on the hunt, is to take a look inside. You want to file down a small blemish with a diamond file. If it's a meteor, you'll be glad you caused as little damage as possible.
Here are those spots after sanding. You should notice the color of the powder that the slime creates. It can often be an instant reference to some of the common iron ores you will come across.
Here you can see that there are no features in the rock on the left. It is an iron ore nodule. However, the rock on the right shows many small iron grains and several small chondrules, which will be discussed in detail later. The rock on the right is the meteorite. What was the rock on the left? As the next two photos will show, the color of the powder when filing the stone is the answer.
As with the normal scratch test done on minerals, red is the color that hematite produces. Hematite is the highest quality iron ore and is often found in small lumps when meteorite hunting. While it doesn't always stick to a magnet, it usually does. Red Hematite powder has been used as a color pigment throughout human history. It's the rouge red from Yes, Rouge. Mixed with animal fat or water, it was the color of cave paintings. But it's the wrong color for mineral dust from meteorites.
Here is the meteorite rock dust. It will almost always be a brown with an older stone. The other most common mineral that sticks to your magnet while hunting is lodestone. It will be a black colored powder and the stone will also be black. Often shows flat crystalline surfaces with a dull black luster when in nodules. These two iron minerals make up a large part of meteorite insects.
It won't be discussed much later, so this is a good time to mention a few other things that actual meteors won't show. Meteors are not porous like lava rocks. With a few exceptions, meteorites are solid on the inside. While the ancient ones may have microscopic cavities where the iron grains have oxidized, the remaining iron is a positive sign that it's a meteorite anyway. So if it has large voids or just bubbles, it's not a meteorite. My first find as a child was a piece of basalt. What he was sure of was a meteorite. I excitedly sent it to the famous "Father of Meteors" Dr. Ninenger. He sent me a nice postcard saying that you have a piece of lava rock. I was so devastated. But a few days later I received a letter with a few pages of material describing real meteorites and what they look like. Thus began his life's journey in the world of meteorites.
Meteors do not contain quartz. Quartz and calcite are the two most common crystals seen when looking for rocks. Meteors do not have shiny crystalline surfaces like terrestrial rocks. Some meteorites have crystals, but the presence of too much iron makes them obvious meteorites.
Meteors do not contain mineral layers. One of the common types of "hot rock" is gneiss with magnetite seen in the black strata running through the rock. Small pieces of this gneiss stick to a magnet and also make it difficult for a metal detector to respond. Eventually, pieces of these gneisses and granites will produce a signal as strong as that of a low-metal meteorite. This is where practice and persistence come in.