Get to know the main groups of meteorite. They differ in their amount of iron-nickel metal and what they reveal about the early solar system.
What are the different types of meteorites?
There are three main types of meteorites:
- iron meteorites:which are almost completely made of metal
- stony-iron meteorites: whichhave nearly equal amounts of metal and silicate crystals
- stony meteorites: whichmostly have silicate minerals
Each group can be split into many more classes and types depending on the minerals, structure and chemistry.
Iron meteorites
Most iron meteorites are thought to be the cores of asteroids that melted early in their history. They consist mainly of iron-nickel metal with small amounts of sulphide and carbide minerals.
During the decay of radioactive elements in the early history of the solar system, many asteroids melted and the iron they contained, being dense, sank to the centre to form a metallic core.
Meteorites from melted asteroids are also known as differentiated meteorites, as they have experienced major chemical or physical changes, solidifying from a molten state.
Sometimes they have an iron core and concentric layers, surrounded by a silicate mantle and crust.
This type of structure is very similar to terrestrial planets (Mercury, Venus, Mars and Earth), which also have metallic cores. Iron meteorites can tell us a great deal about how the metallic cores of planets formed.
Iron meteorites are mainly made of an iron-nickel alloy with a distinctive crystalline structure known as a Widmanstätten texture. Bands are formed by varying levels of nickel.
There can be wide variation in the texture and mix of minerals present within iron meteorites, which will produce many groups and subtypes.
Stony-iron meteorites
Stony-iron meteorites consist of almost equal parts iron-nickel metal and silicate minerals including precious and semi-precious gemstones. They are considered some of the most beautiful meteorites. There are two different types of stony-iron meteorites: pallasite and mesosiderite.
Pallasites
Pallasites contain big, beautiful olive-green crystals - a form of magnesium-iron silicate called olivine - embedded entirely in metal. Sometimes the olivine does not occur as a single crystal but as a cluster. Elsewhere it can create a pattern of veins through solid metal.
The scientific jury is still out on exactly how pallasite meteorites formed. Some scientists believe they formed in melted asteroids in a similar way to iron meteorites, where dense iron metal sinks toward the centre to form an iron core.
Pallasites are thought to be samples of the boundaries between a metal core and the silicate, olivine-rich mantle around it. If this is the case, they could tell us a lot about the formation of Earth and other terrestrial planets.
However, other scientists think that there are very few olivine-rich meteorites in the asteroid belt, and too many pallasite meteorites for them all to have come from a core-mantle boundary. These types of formations may also be formed by impact melting.
See a pallasite meteorite on display in Hintze Hall.
Mesosiderites
Mesosiderite meteorites are breccias, a variety of rock composed of broken fragments of minerals or rock cemented together by a finer material. The fragments are roughly centimetre-sized and contain a mix of igneous (solidified) silicate and metal clasts (rocks made of pieces of older rocks).
Mesosiderites form when debris from a collision between two asteroids is mixed together. In the crash, molten metal mixes together with solid fragments of silicate rocks. Mesosiderites can therefore both record the history of both meteorites and reveal a snapshot of the conditions required for asteroids to melt and form iron cores.
Stony meteorites
The majority of meteorite finds are stony meteorites, consisting mostly of silicate minerals.
There are two main types of stony meteorite: chondrites (some of the oldest materials in the solar system) and achondrites (including meteorites from asteroids, Mars and the Moon).
Both chondrites and achondrites have many subgroups based on their compositions, structures and the minerals they contain.
Chondrites
At over 4.5 billion years old, chondrites are some of the most primitive and pristine rocks in the solar system and have never been melted.
Chondrites have a distinctive appearance, made from droplets of silicate minerals mixed with small grains of sulphides and iron-nickel metal. Their millimetre-sized granules give chondrites their name, from the Greek 'chondres' meaning sand grains.
There are many varieties of chondrite, with differences in mineralogy relating to the type of asteroid the meteorite came from.
Chondrites are the material from which the solar system formed. They have been little changed compared with rocks from larger planets, which have been subjected to geological activity. Chondrites can tell us a lot about how the solar system formed.
The Murchison meteorite that fell in Australia in 1969 is a chondrite. It's also smells a bit like Brussels sprouts. Dr Helena Bates explains why.
The most basic types, known as carbonaceous chondrites, are rich in water, sulphur and organic material. They are thought to have brought volatile material to Earth when it was newly formed, helping to establish the atmosphere and other conditions required to sustain life.
Achondrites
Achondrites include meteorites from asteroids, Mars and the Moon. They are igneous, meaning at some point they were melted into magma. When magma cools and crystallises, it creates a concentric layered structure. This process is known as igneous differentiation.
The rocky planets Mercury, Venus, Earth and Mars were formed in this way, giving them planetary crusts, mantles and cores. Achondrites can tell us a lot about the internal structure and formation of the planets, including our own.
Want to find out even more about meteorites? Check out our handy FAQ.
FAQs
There are three major types of meteorites: the "irons," the "stonys," and the "stony-irons." Although the majority of meteorites that fall to Earth are stony, most of the meteorites discovered long after they fall are irons. Irons are heavier and easier to distinguish from Earth rocks than stony meteorites.
What are meteors' answers? ›
Meteor Description. A meteor is a space rock that enters earth's atmosphere causing a streak of light to appear in the sky. These are sometimes referred to as shooting stars. Meteors are formed from meteoroids that enter earth's atmosphere.
What are the types of meteorites? ›
Meteorites have traditionally been divided into three broad categories: stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material.
What are 10 facts about meteorites? ›
10 Things You Need To Know About Meteors
- #1 - They Were Once Thought to Be an Atmospheric Phenomenon.
- #2 - Meteors Occur When a Meteoroid Burns Up in the Atmosphere.
- #3 - A Fireball Is a Meteor Brighter Than the Planet Venus.
- #4 - Meteorites Reach the Ground.
- #5 - There Are 9 Major Meteor Showers and 103 Minor Showers.
There are three main types of meteorites:
- iron meteorites: which are almost completely made of metal.
- stony-iron meteorites: which have nearly equal amounts of metal and silicate crystals.
- stony meteorites: which mostly have silicate minerals.
Meteoroids are lumps of rock or iron that orbit the sun, just as planets, asteroids, and comets do. Meteoroids, especially the tiny particles called micrometeoroids, are extremely common throughout the solar system.
What is asteroid short answer? ›
The Short Answer:
Asteroids are small, rocky objects that orbit the Sun. Although asteroids orbit the Sun like planets, they are much smaller than planets. Asteroids are small, rocky objects that orbit the sun. Although asteroids orbit the sun like planets, they are much smaller than planets.
What is a rare meteorite? ›
Some of the rarest types of meteorites, the achondrites, do not attract magnets for the same reason that most earth rocks do not attract magnets – they do not contain iron-nickel metal. Achondrites are rare, however. Only 2.5% of the ~1500 stony meteorites that have been found in the U.S. are achondrites.
What is a meteor for kids? ›
We know of these as shooting stars, but the real term for a shooting star is a meteor. A meteor is any piece of comet, meteoroid, or asteroid that travels into Earth's atmosphere. Millions of these objects are zipping around in space all the time, but occasionally they enter Earth's atmosphere.
How do I classify my meteorite? ›
Traditional classification scheme
Meteorites are often divided into three overall categories based on whether they are dominantly composed of rocky material (stony meteorites), metallic material (iron meteorites), or mixtures (stony–iron meteorites).
During a meteorite's 10- to 15-second trip through the atmosphere, air friction heats its surface to a red-hot 1,800 degrees Celsius. This friction can melt the meteorite, and can carry away up to 90 percent of the original mass, leaving interesting surface features.
Do meteorites burn up? ›
Meteors burn as they fall through the mesosphere. The space rocks experience friction with the gas molecules. The friction makes the meteors get very hot. Many meteors burn up completely in the mesosphere.
What does a meteor look like? ›
Meteors appear in different colors, depending on the chemical composition of the space rock and the air it is passing through. A meteor with high iron content, for instance, will appear yellow. A meteor with high calcium content may appear as a purple streak of light.
Can meteorites have bubbles? ›
Nearly all meteorites contain iron-nickel metal and attract magnets easily. Check for holes or bubbles in the specimen. A true meteorite will not have any holes or bubbles at all. If your specimen does, it's likely slag or some other stony matter.
Do all meteorites have diamonds? ›
Diamonds, lonsdaleite, carbonados, stishovite, tridymite, and occur in some meteorites but they all occur as microscopically small grains that can only be seen with aid of a microscope or other expensive instruments like a scanning electron microscope (SEM).
Is my rock a meteorite? ›
The USGS doesn't verify meteorites, but they have several properties that help distinguish them from other rocks: Density: Meteorites are usually quite heavy for their size, since they contain metallic iron and dense minerals. Magnetic: Since most meteorites contain metallic iron, a magnet will often stick to them.
What is a meteor explained? ›
Meteors: When meteoroids enter Earth's atmosphere (or that of another planet, like Mars) at high speed and burn up, the fireballs or “shooting stars” are called meteors. Meteorites: When a meteoroid survives a trip through the atmosphere and hits the ground, it's called a meteorite.
What is a meteor in your own words? ›
A meteor is space matter that has entered Earth's atmosphere, as in I was able to see a meteor enter our atmosphere last night through my telescope. A meteor is also the bright, fiery streak that is visible in the sky when a meteor burns up. Meteors are often referred to as shooting stars or falling stars.
What is a meteor shower answer? ›
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories.
What is a meteor in science sentence? ›
Last year, light from a bright moon washed out many of the meteors. The agency said the last meteor storm occurred in 2002. The meteors from this shower appear to emanate from this area of stars in the night sky.
