To identify whether a sample is a meteorite, we can consider the following aspects:

1. External melting crust: Meteorites will pass through the dense atmosphere before falling to the ground. During the falling process, the meteorite will rub with the atmosphere to produce high temperature, which will melt its surface and form a thin melting shell. Therefore, all newly landed meteorites have a black molten shell with a thickness of about1mm.

2. Surface air marks: In addition, due to the interaction between meteorites and large airflow, many air marks will be left on the surface of meteorites, just like fingerprints pressed by fingers.

3. Internal metal: Iron meteorites and stone iron meteorites are composed of metallic iron, which has a high nickel content (5- 10%). There are also metal particles in chondrites, and fine metal particles can be seen on fresh fractures.

4. Magnetism: Because most meteorites contain iron, 95% of meteorites can be attracted by magnets.

5. Sphere: Most meteorites are chondrites (accounting for 90% of the total), and there are a lot of silicate spheres in these meteorites, which are called chondrites. A round chondrite can be seen on the fresh fracture of chondrite.

6. Specific gravity: The specific gravity of iron meteorites is 8g /cm3, which is much larger than that of ordinary rocks on the earth. Because chondrites contain a small amount of metals, their specific gravity is also very heavy.

Meteorite, when not falling into the earth's atmosphere, is a kind of stone, iron or a mixture of stone and iron floating in outer space. If it falls into the atmosphere, it will become a meteorite that we usually see falling to the ground without being burned by the atmosphere. Simply put, the so-called meteorite is the debris left by a tiny asteroid "hitting the earth".

China is the first country to find meteorites in the world. It was in the Neolithic Age, and then it was recorded in writing until the end of the 20th century. There are many names marked by "meteorite", such as "Meteor Mountain" and "Meteor Lake".

Meteorites are generally divided into three categories according to composition, namely iron meteorites, also known as meteorites. Generally, the contents of iron and nickel are above 95%, including 80% ~ 95% of iron and 5% ~ 20% of nickel. The density is 8 to 8.5. Other components may include sulfides, diamonds, rare earth elements and silicates. Iron meteorites account for about 3% of the total meteorites. The world No.3 iron meteorite was discovered in Qinghe, Xinjiang, China at the end of 19, with a size of 2.42× 1.85× 1.37 and a weight of about 30 tons. This meteorite contains 88.67% iron and 9.27% nickel. It contains many kinds of minerals that are not found on the earth, such as pyrite, zeolite and other cosmic minerals.