Once you find what you think is a meteorite, you can use a series of tests to try identify a meteorite your find or a simple stone. To know how to identify a meteorite you must first know the types of meteorite. There are many characteristics that will help in identification.
Most meteorites containing iron, as a rule, have magnetic properties. Even outwardly, the meteorite differs from an ordinary stone. They tend to be heavier and much denser than regular Earth rocks, due in part to their high iron content. Also, meteorites contain higher concentrations of nickel compared to ordinary rocks of the Earth. You can use nickel tests to check for the presence of nickel in a test sample.
When viewed under magnification, the inside of a stony meteorite will contain not only iron spots within the stone, but also small, spherical mineral inclusions, which are called chondrules. will be scattered throughout the matrix. The matrix is the material surrounding the chondrules and inclusions of iron. Even by these indicators, a meteorite can be identified.
There are 3 main types of meteorites: stony meteorites, iron meteorites and stony iron meteorites. As the name suggests
stony iron meteorites usually consist of a 50/50 mixture of iron and silicate minerals. There are two types of stony-iron meteorite: pallasite and mesosiderite - they are a very rare type of meteorite and make up about 1-5% of all meteorites. It is very difficult to identify such meteorites.
Iron meteorites make up about 5% of all known meteorites, and although this figure varies from source to source, most would agree that this is accurate.
Stony meteorites (ordinary chondrites) make up the majority, 80% to 95% of all meteorites that fall to earth. They are called chondrites because of the small spherical inclusions called chondrules discussed above. These minerals are formed in a vacuum environment with zero gravity space, so they have such a shape. They are easy to identify in a meteorite.
You can identify a meteorite by the presence of a burnt and melted surface of a fallen meteorite, which also demonstrates what is called a meteorite melting crust. It is a thin veneer of black material that forms on the surface of a rock, a meteoroid that enters our atmosphere. As a rule, this dark black melt crust is very similar on the outside to coal, but if the meteorite is a stone type, then it usually has a light interior that looks just like concrete.
Another very important indicator of determining a meteorite is regmaglipts or imprints. These grooves, ridges, dippers, and depressions on the surface of a meteorite are formed in a process called ablation. This happens the moment a meteoroid passes through our atmosphere. At very high temperatures, less dense layers from the surface of the stone begin to melt, and this creates rounded depressions, known as fingerprints. Fingerprints are so called because the human finger usually fits perfectly into these depressions.
There are many more methods for identifying meteorites than the methods mentioned here, but if you have a rock that matches these characteristics, then you can be more certain that it is a meteorite. If you find a meteorite, what to do next? Go to the Meteoritics Laboratory website page. Perhaps you will find the answer there.
Your best bet would be to get in touch with specialists or meteorite experts who can help you identify the meteorites. There are many professional meteorite hunters who know and meteorite shop dealers who will be happy to help you identify a meteorite or give you guidance in finding the right specialist. Where do meteorites come from you can read.
P.S. If you find what you think is a meteorite, send a description and photos of your find, and our readers will see it, and they will help determine the value of the stone. Read more in the Rubric
Often a common person imagining what a meteorite looks like, thinks of iron. And it's easy to explain. Iron meteorites are dense, very heavy, and often take on unusual and even impressive shapes as they fall and melt in our planet's atmosphere. And although iron is associated with the typical composition of space rocks in most people, iron meteorites are one of the three main types of meteorites. And they are quite rare compared to stony meteorites, especially the most common group of them - single chondrites.
Three main types of meteorites
There is a large number meteorite types, divided into three main groups: iron, stone, stone-iron. Almost all meteorites contain extraterrestrial nickel and iron. Those that do not contain iron at all are so rare that even if we ask for help identifying possible space rocks, we will most likely not find anything that does not contain a large amount of metal. The classification of meteorites is, in fact, based on the amount of iron contained in the sample.
iron meteorites
iron meteorites were part of the core of a long-dead planet, or big asteroid, from which it is believed to have formed Asteroid Belt between Mars and Jupiter. They are the densest materials on Earth and are very strongly attracted to a strong magnet. Iron meteorites are much heavier than most of the Earth's rocks, if you've lifted a cannonball or a slab of iron or steel, you know what I'm talking about.
In most samples of this group, the iron component is approximately 90% -95%, the rest is nickel and trace elements. Iron meteorites are divided into classes according to their chemical composition and structure. Structural classes are determined by examining two components of iron-nickel alloys: kamacite and taenite.
These alloys have a complex crystal structure known as the Widmanstetten structure, named after Count Alois von Widmanstetten, who described the phenomenon in the 19th century. This lattice-like structure is very beautiful and is clearly visible if the iron meteorite is cut into plates, polished and then etched in a weak solution. nitric acid. For kamacite crystals found in the process, the average band width is measured and the resulting figure is used to separate iron meteorites into structural classes. Iron with a thin band (less than 1 mm) is called "fine-structured octahedrite", with a wide band "coarse octahedrite".
stone meteorites
The largest group of meteorites - stone, they formed from the outer crust of a planet or asteroid. Many stony meteorites, especially those that have been on the surface of our planet for a long time, are very similar to ordinary terrestrial stones, and it takes an experienced eye to find such a meteorite in the field. Recently fallen rocks have a black lustrous surface that was formed by the burning of the surface in flight, and the vast majority of rocks contain enough iron to be attracted to a powerful magnet.
Some stony meteorites contain small, colorful, grain-like inclusions known as "chondrules". These tiny grains originated from the solar nebula, therefore, even before the formation of our planet and the whole solar system, making them the oldest known matter available for study. Stony meteorites containing these chondrules are called "chondrites".
Space rocks without chondrules are called "achondrites". These are volcanic rocks formed by volcanic activity on their "parent" space objects, where melting and recrystallization have erased all traces of ancient chondrules. Achondrites contain little or no iron, making it difficult to find compared to other meteorites, although specimens often have a glossy crust that looks like enamel paint.
Stone meteorites from the Moon and Mars
Can we really find lunar and Martian rocks on the surface of our own planet? The answer is yes, but they are extremely rare. More than one hundred thousand lunar and about thirty Martian meteorites have been found on Earth, and all of them belong to the achondrite group.
The collision of the surface of the Moon and Mars with other meteorites threw fragments into outer space and some of them fell to the ground. From a financial point of view, lunar and Martian samples are among the most expensive meteorites. In the collectors' markets, they cost up to a thousand dollars per gram, which makes them several times more expensive than if they were made of gold.
Stony-iron meteorites
The least common of the three main types - stone-iron, accounts for less than 2% of all known meteorites. They consist of approximately equal parts of iron-nickel and stone, and are divided into two classes: pallasite and mesosiderite. Stone-iron meteorites were formed at the border of the crust and mantle of their "parent" bodies.
Pallasites are perhaps the most enticing of all meteorites and are definitely of great interest to private collectors. Pallasite is composed of an iron-nickel matrix filled with olivine crystals. When olivine crystals are clear enough to appear emerald green, they are known as a perodot gemstone. Pallasites got their name in honor of the German zoologist Peter Pallas, who described the Russian meteorite Krasnoyarsk, found near the capital of Siberia in the 18th century. When a pallasite crystal is cut into slabs and polished, it becomes translucent, giving it an ethereal beauty.
Mesosiderites are the smaller of the two stony-iron groups. They are composed of iron-nickel and silicates and are usually attractive. The high contrast of the silver and black matrix, when the plate is cut and sanded, and the occasional blotch, results in a very unusual look. The word mesosiderite comes from the Greek for "half" and "iron" and they are very rare. In thousands of official catalogs of meteorites, there are less than a hundred mesosiderites.
Classification of meteorites
Meteorite classification is a complex and technical subject and the above is only intended as a brief overview of the topic. Classification methods have changed several times over the years. last years; known meteorites were reclassified to another class.
The fall of the meteorite is very short and always unexpected. This can happen at any time of the day and year, the place of the fall can also be any. Imagine how many meteorites lie at the bottom of the seas, rivers and lakes?Search engines sometimes find heavy rusty rocks that the metal detector reacts to, but not everyone realizes that this could be a meteorite!
By what signs can one determine that the found stone is actually a meteorite? ..
What are hot stones?
If you use a meteorite-oriented metal detector, then when you find a stone that gives a response to the device, you can assume that a meteorite has been found. However, it can not only be a meteorite, but also “ hot stone” (hot rock - English). This is a fairly common occurrence. What it is?“Hot stones” give the same clear signal as a metal object. Unlike a metal object, the signal from a “hot stone” disappears when the searchcoil moves slightly away from it.
Practically accurate information on the study of "hot stones" is scarce, but it is known that these rocks contain inclusions of magnetite (iron ore), chalcopyrite (copper ore) or other electrically conductive and magnetic minerals.
How to distinguish a meteorite from an ordinary stone? Signs of a meteorite
How to distinguish a meteorite from slag? First of all, you need to have an idea about . There are also characteristic and most important signs of meteorite identification and identification when searching for meteorites:1. Most meteorites have magnetic properties (reaction of a metal detector to an object, they are attracted by a magnet)
2. Characteristic dark gray, black, dark brown or dark red color of the outer surface (the outer surface may also be shiny)
3. The outer surface is melted after passing through the atmosphere
4. When passing through the atmosphere and being exposed to very high temperatures, less dense matter “melts” from the surface of the meteorite. This phenomenon creates notches, ridges and depressions with rounded borders (regmaglipts), resembling fingerprints on clay or plasticine.
5. On the break, inclusions of metals and minerals of other colors are visible (not always visible without magnification)
6. Meteorites are not like Earth's rocks
7. Meteorites tend to be heavier and much denser than regular terrestrial rocks.
When searching for meteorites, the observation of the search engine and can be of great help in identifying the find. To do this, you need to know what different types of meteorites look like (you can even have photographs with you).
If you have the opportunity to set up a metal detector using real meteorites, then do it by all means (this is meteorite calibration).
Good luck!
related tags: meteorites, search for meteorites, differences between a meteorite and a stone, how to distinguish a meteorite from a stone, hot stones, signs of a meteorite, identification of meteorites, how to distinguish a meteorite from slag, definition of a meteorite
SELF AUTHENTICATION
Meteorite- this is an extraterrestrial, cosmogenic substance, unique in its composition and structure - it is almost impossible to fake or repeat it.
If you are trying to verify the authenticity of a meteorite for the first time, we will tell you how to do it. Sometimes it is really not easy to distinguish cosmic matter from terrestrial minerals or alloys, guided only by external signs, although if you already have experience, these words rather refer to new or rare meteorites, since most samples of already common and long-known meteorites are more or less easily comparable and recognizable.
Below is a well-known list of meteorite signs with our corrections and additions:
1. Fresh specimens show melting crust [see description below, applies to all meteorites]
2. High density: meteorites are heavier than, for example, granite or sedimentary rocks. [all meteorites]
3. Sometimes oriented-conical or fused-detrital shape [all meteorites]
4. They can be smooth, but more often regmaglipts are visible on the surface - smoothed depressions resembling finger dents in clay. [all meteorites]
5. The fracture is most often gray in color, on which small, about 1 mm in size balls - chondrules are sometimes noticeable. [stone chondrites only]
6. In the majority, inclusions of metallic iron are visible on the polished section. [all stone]
7. Magnetization: The compass needle deviates noticeably. You can also use a rare earth magnet for stone meteorites. [everything except stone ashodnrites]
8. Over time, they oxidize in air, acquiring a brown, rusty color. [all but achondrites]
9. Can be forged without special heating to high temperatures. [iron]
10. On a polished and acid-etched section, Widmanstatt figures or Neumann lines appear. [all iron except ataxites]
What meteorites do not have:
1. Missing layers. Layering is often observed in shale sandstones, jasper-like rocks.
2. There are no carbonate rocks like chalk, limestone, dolomite.
3. Fossils are not found: shells, fossil fauna imprints.
4. There is no large crystalline structure like granite.
5. They do not fall hot and cannot cause burns or fires. At the same time, they often remain cold inside, as they were in space.
“The most striking feature of every meteorite is the melting crust. If the meteorite did not break during its fall to the Earth, or if it was not broken by someone later, then it is covered on all sides with a melting crust. The color and structure of the melting crust depends on the type of meteorite. Often the melting crust of iron and stony-iron meteorites is black, sometimes with a brownish tint. The melting crust on stony meteorites is especially clearly visible; it is black and dull, which is characteristic mainly of chondrites. However, sometimes the bark is very shiny, as if covered with black varnish; this is characteristic of achondrites. Finally, a light, translucent crust is very rarely observed, through which the material of the meteorite is translucent. The melting crust is observed, of course, only on those meteorites that were found immediately or shortly after their fall. Meteorites that have lain in the Earth for a long time are destroyed from the surface under the influence of atmospheric and soil agents. As a result, the melting crust is oxidized, weathered and turns into an oxidation or weathering crust, taking on a completely different look and properties. Kazakov D. A.
“In order to confirm the cosmic origin of an object, it is necessary to identify at least the slightest signs of iridium in its body. Iridium is a rare earth metal. Finding it is harder than gold or even platinum. Accordingly, it costs much more. Iridium is almost always found in meteorites. In very small proportions. From one kilogram space stone, you can scrape off two or three thousandths of a gram at most. This is a kind of quality mark" - Nikolaichuk A.
AUTHENTICATION BY EXPERTS
In Moscow, there are a number of institutions where you can at any time carry out the necessary analysis of a potentially meteorite substance. If you find, for example, a stone that looks like a meteorite, you need to send it by parcel post for examination to the Laboratory of Cosmochemistry and Meteoritics of the Institute of Geochemistry and analytical chemistry RAN. It is not necessary to send the whole meteorite, a small fragment is enough. The parcel must be accompanied by a letter with a return address, a detailed description of the circumstances under which the find was made, and the exact coordinates of the place where the object was found.
Upon receipt of your parcel, the laboratory staff is obliged to perform a free qualified analysis of the sent sample and inform you of the results, even if it does not turn out to be a meteorite. If you really became the owner of a meteorite, then according to the rules established by the International Nomenclature Committee for registering your sample in the International Catalog of Meteorites, it is necessary that 20% of the stone be in a scientific institution (since all meteorites are of great scientific value). For citizens of the Russian Federation, this is GEOKHI RAS, which is the custodian of the meteorite collection Russian Academy Sciences.
