<blockquote>
  <p>What is lava called if it has 56% to 64% silica?</p>
</blockquote>

<p>It's called <a href="https://duckduckgo.com/?q=igneous%20classification&amp;ia=images&amp;iax=images" rel="noreferrer">intermediate</a>.</p>

<blockquote>
  <p>Or is it impossible for any lava to cool into rocks with that range of silica?</p>
</blockquote>

<p>Not impossible, but not common. The two most common lava types are indeed mafic (mostly basalts) and felsic (mostly rhyolite). A well known intermediate lava type is andesite.</p>

<blockquote>
  <p>Why?</p>
</blockquote>

<p>This question of why most lavas are either mafic or felsic has been bothering geologists for a very long time. This problem even has a name: the "Daly gap", named after the geologist who first identified the problem almost 100 years ago. There is no easy answer, and it's still being debated. A good (yet somewhat technical) read is available here in this <a href="https://www.researchgate.net/post/The_Daly_Gap_where_are_the_missing_andesites" rel="noreferrer">ResearchGate question and following answers</a>.</p>

CC BY-SA 4.0
2018-11-22T09:56:27.950Z
2018-11-22T09:56:27.950Z
Gimelist
<p>We've learnt in science at school that "Mafic" lava forms rocks with 45% to 55% silica, meanwhile "Felsic" lava forms rocks with >=65% silica. So what is lava called in between? Or is it impossible for any lava to cool into rocks with that range of silica? Why?</p>

CC BY-SA 4.0
2018-11-22T08:06:11.813Z
My geology is rusty but I would say it's called 'intermediate'. See [this image](https://www.quora.com/Is-mafic-always-either-ferromagnesian-or-felsic).
Bollehenk
CC BY-SA 4.0
2018-11-22T08:07:27.013Z
Also see: [geologyin.com](http://www.geologyin.com/2014/12/how-to-classify-igneous-rocks-into.html)
Bollehenk
<volcanology><igneous>
What is lava called if it has 56% to 64% silica?
PolymorphismPrince
# What is lava called if it has 56% to 64% silica?

(Asked by: username_0 on 2018-11-22)

We've learnt in science at school that "Mafic" lava forms rocks with 45% to 55% silica, meanwhile "Felsic" lava forms rocks with >=65% silica. So what is lava called in between? Or is it impossible for any lava to cool into rocks with that range of silica? Why?

**Tags:** volcanology, igneous

> **Comments:**
> **username_1**: My geology is rusty but I would say it's called 'intermediate'. See [this image](https://www.quora.com/Is-mafic-always-either-ferromagnesian-or-felsic).  
> **username_1**: Also see: [geologyin.com](http://www.geologyin.com/2014/12/how-to-classify-igneous-rocks-into.html)  

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## 1 answers

### Answer by username_2 on 2018-11-22. Score: 6 | Accepted answer

> What is lava called if it has 56% to 64% silica?

It's called [intermediate](https://duckduckgo.com/?q=igneous%20classification&ia=images&iax=images).

> Or is it impossible for any lava to cool into rocks with that range of silica?

Not impossible, but not common. The two most common lava types are indeed mafic (mostly basalts) and felsic (mostly rhyolite). A well known intermediate lava type is andesite.

> Why?

This question of why most lavas are either mafic or felsic has been bothering geologists for a very long time. This problem even has a name: the "Daly gap", named after the geologist who first identified the problem almost 100 years ago. There is no easy answer, and it's still being debated. A good (yet somewhat technical) read is available here in this [ResearchGate question and following answers](https://www.researchgate.net/post/The_Daly_Gap_where_are_the_missing_andesites).


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