# What holds sandstone together?

**URL:** <https://boards.straightdope.com/t/what-holds-sandstone-together/263082>\
**Category:** Factual Questions\
**Created:** [September 4, 2004, 4:41am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082 "2004-09-04T04:41:29Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [September 4, 2004, 4:41am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082/1 "2004-09-04T04:41:29Z")

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Just curious.

[This Wikipedia link re sandstone](http://en.wikipedia.org/wiki/Sandstone) says calcite, clays and silica “cement” the grains together, but no explantion as to how this “cementing” occurs.

What’s happening in this “cementing” process?

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [September 4, 2004, 4:45am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082/2 "2004-09-04T04:45:57Z")

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Something sedimentary, I would suppose.  
🙂

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [September 4, 2004, 4:52am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082/3 "2004-09-04T04:52:20Z")

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> [@carnivorousplant](#):
>
> Something sedimentary, I would suppose.  
> 🙂

No kidding! :eek:

I guess I’m really looking for the specific physical/chemical interaction(s) that causes this “cementing” process to happen. Why does this this lightweight, porus rock stay together?

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [September 4, 2004, 4:59am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082/4 "2004-09-04T04:59:08Z")

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Sorry, I wanna know, too.

Ever since I was a kid, breaking a rock open and finding sand inside I could rub away with my thumb.

Guess I should have just subscribed. 🙂

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**Author:** ![Doobieous](https://avatars.discourse-cdn.com/v4/letter/d/da6949/32.png) [@Doobieous](https://boards.straightdope.com/u/Doobieous)\
**Post date:** [September 4, 2004, 11:56am UTC](https://boards.straightdope.com/t/what-holds-sandstone-together/263082/5 "2004-09-04T11:56:28Z")

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> [@astro](#):
>
> Just curious.
> 
> [This Wikipedia link re sandstone](http://en.wikipedia.org/wiki/Sandstone) says calcite, clays and silica “cement” the grains together, but no explantion as to how this “cementing” occurs.
> 
> What’s happening in this “cementing” process?

Crystalization, which binds the sand grains and locks them in. Much like the crystalizing of the lime in cement, holds the sand and aggregates in place.  
calcite can precipitate out (much like it can in hard water). Silica can also precipitate out of ground water and crystalize cementing beds of sand together to form sandstone (it can also fill spheroids, or form geodes). Iron oxide can also cement sand together as well.