<p>For magma and lava it's liked you said: "magma" is used under the surface, "lava" above. See for instance <a href="https://volcanoes.usgs.gov/vsc/glossary/lava.html" rel="nofollow noreferrer">the definition of USGS Volcano Hazard Program's glossary</a>:</p>

<blockquote>
  <p><strong>Lava</strong>: General term for magma (molten rock) that has been erupted onto the surface of the Earth and maintains its integrity as a fluid or viscous mass, rather than exploding into fragments.</p>
</blockquote>

<p>Now, does this simple location change justify another term? I would argue that yes, for this reason: <strong>if all lavas have once been magmas, all magmas will not become lava</strong>.</p>

<p>The fate of magmas can vary. Some will form plutons and crystallize inside the crust instead of reaching the surface. Granites, for instance, have once been magmas. This is why the main rock type "magmatic rocks" is subdivided into two subcategories: plutonic rocks and volcanic rocks. Even in the volcanic subcategory, all rocks are not lavas. As the USGS definition suggests, only a magma erupted effusively becomes a lava. A magma erupted explosively generates another type of volcanic rocks: <a href="https://volcanoes.usgs.gov/vsc/glossary/tephra.html" rel="nofollow noreferrer">tephra</a>.</p>

CC BY-SA 4.0
2020-01-07T14:16:02.453Z
2020-01-07T14:16:02.453Z
Jean-Marie Prival
<p>There is a real difference between lava and magma. Magma contains lots of water and various gases. When it reaches earth's surface, it looses most of its volatiles and becomes lava.</p>

<p>So, magma is volatile rich lava.    </p>

CC BY-SA 3.0
2016-07-04T18:59:24.617Z
What about the other half of the question?
bon
CC BY-SA 3.0
2016-07-05T08:47:52.373Z
I said all I know...
longira
CC BY-SA 3.0
2016-07-04T09:34:53.057Z
2016-07-04T10:35:56.217Z
2016-07-04T10:35:56.217Z
longira
<p>Some features of Earth (and beyond) have been bugging me for quite some time.  When molten rock is beneath the surface, it's called "magma".  Above the surface, it is called "lava".  When a bolide is in orbit of any planet, it's called a "meteoroid".  When it makes contact with the atmosphere, it becomes a "meteor".  When it hits the surface, it becomes a "meteorite".  But changing one's name based on a change in location is, at best, superficial and has no relation to chemistry and composition.</p>

<p>Are there any REAL differences between magma and lava?  Are there any REAL differences between a meteoroid, a meteor and a meteorite?  If not, then why do we call them by different names?</p>

CC BY-SA 3.0
2016-07-04T07:29:18.137Z
Couldn't the same thing be said about Rain and Water?   Different names for where things are and what they do or just did isn't a bad idea, though I will admit that the Meteroid/ite/Meteor to me always seemed a bit unnecessary but I might not feel that way if I was a professional astronomer.   Magma/Lava never bothered me.
userLTK
CC BY-SA 3.0
2016-07-04T10:42:38.453Z
Actually, the composition of meteoroid changes when it becomes ad meteor and a meteorite. While being a meteor, most volatile compounds evaporate and chemical organic compounds are destroyed. Hence, the composition of meteoroids and meteorites differs. Moreover, one meteor may break into several parts. There might be more differenceres.
daniel.heydebreck
<volcanology><meteorite>
Lava and Magma, Meteor and Meteorite--What's the Difference?
JohnWDailey
# Lava and Magma, Meteor and Meteorite--What's the Difference?

(Asked by: username_0 on 2016-07-03)

Some features of Earth (and beyond) have been bugging me for quite some time. When molten rock is beneath the surface, it's called "magma". Above the surface, it is called "lava". When a bolide is in orbit of any planet, it's called a "meteoroid". When it makes contact with the atmosphere, it becomes a "meteor". When it hits the surface, it becomes a "meteorite". But changing one's name based on a change in location is, at best, superficial and has no relation to chemistry and composition.

Are there any REAL differences between magma and lava? Are there any REAL differences between a meteoroid, a meteor and a meteorite? If not, then why do we call them by different names?

**Tags:** volcanology, meteorite

> **Comments:**
> **username_1**: Couldn't the same thing be said about Rain and Water?   Different names for where things are and what they do or just did isn't a bad idea, though I will admit that the Meteroid/ite/Meteor to me always seemed a bit unnecessary but I might not feel that way if I was a professional astronomer.   Magma/Lava never bothered me.  
> **username_2**: Actually, the composition of meteoroid changes when it becomes ad meteor and a meteorite. While being a meteor, most volatile compounds evaporate and chemical organic compounds are destroyed. Hence, the composition of meteoroids and meteorites differs. Moreover, one meteor may break into several parts. There might be more differenceres.  

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## 2 answers

### Answer by username_3 on 2020-01-07. Score: 1 | Accepted answer

For magma and lava it's liked you said: "magma" is used under the surface, "lava" above. See for instance [the definition of USGS Volcano Hazard Program's glossary](https://volcanoes.usgs.gov/vsc/glossary/lava.html):

> **Lava**: General term for magma (molten rock) that has been erupted onto the surface of the Earth and maintains its integrity as a fluid or viscous mass, rather than exploding into fragments.

Now, does this simple location change justify another term? I would argue that yes, for this reason: **if all lavas have once been magmas, all magmas will not become lava**.

The fate of magmas can vary. Some will form plutons and crystallize inside the crust instead of reaching the surface. Granites, for instance, have once been magmas. This is why the main rock type "magmatic rocks" is subdivided into two subcategories: plutonic rocks and volcanic rocks. Even in the volcanic subcategory, all rocks are not lavas. As the USGS definition suggests, only a magma erupted effusively becomes a lava. A magma erupted explosively generates another type of volcanic rocks: [tephra](https://volcanoes.usgs.gov/vsc/glossary/tephra.html).


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### Answer by username_4 on 2016-07-04. Score: 2

There is a real difference between lava and magma. Magma contains lots of water and various gases. When it reaches earth's surface, it looses most of its volatiles and becomes lava.

So, magma is volatile rich lava.

> **Comments:**
> **username_5**: What about the other half of the question?  
> **username_4**: I said all I know...  

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