# What kind of clay is used in pencils?

**URL:** <https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294>\
**Category:** Factual Questions\
**Created:** [October 1, 2009, 11:43pm UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294 "2009-10-01T23:43:04Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Picard\_Kills\_Kirk](https://avatars.discourse-cdn.com/v4/letter/p/dec6dc/32.png) [@Picard\_Kills\_Kirk](https://boards.straightdope.com/u/Picard_Kills_Kirk)\
**Post date:** [October 1, 2009, 11:43pm UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294/1 "2009-10-01T23:43:04Z")

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I know that pencil “lead” is a combination of graphite and clay. I have tried to google what type of clay is used, but I am unable to find any solid answers. I have seen a [video](http://www.pencils.co.uk/modules/heritage/videos/core.aspx) where they mention the use of china clay (which appears to be kaolin) in colored pencils, and one vague reference to pipe clay. Any help would be appreciated. Thanks!

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**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\
**Post date:** [October 2, 2009, 12:08am UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294/2 "2009-10-02T00:08:30Z")

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The other clay used is sodium bentonite. Commonly called just Bentonite. It is a fine grey powdered clay used in lots of things. Binder and flow agents in feed manufacture and is also used in drilling mud for oil rigs.

The graphite comes from recycling of pot liners used in the aluminium industry. This link has probably more than you really want to know about pencil lead manufacture:

[http://www.patentstorm.us/patents/7217378/description.html](http://www.patentstorm.us/patents/7217378/description.html)

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**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\
**Post date:** [October 2, 2009, 12:16am UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294/3 "2009-10-02T00:16:27Z")

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Missed the too short edit window. If that link is not to your liking, just search using both bentonite and pencil lead and you will get pages of information to choose from.

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**Author:** ![Picard\_Kills\_Kirk](https://avatars.discourse-cdn.com/v4/letter/p/dec6dc/32.png) [@Picard\_Kills\_Kirk](https://boards.straightdope.com/u/Picard_Kills_Kirk)\
**Post date:** [October 2, 2009, 2:30am UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294/4 "2009-10-02T02:30:07Z")

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Thank you, **Ghardester**! This is exactly what I am looking for.

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**Author:** ![Insightfulwiz267](https://avatars.discourse-cdn.com/v4/letter/i/ccd318/32.png) [@Insightfulwiz267](https://boards.straightdope.com/u/Insightfulwiz267)\
**Post date:** [November 8, 2010, 3:45pm UTC](https://boards.straightdope.com/t/what-kind-of-clay-is-used-in-pencils/512294/5 "2010-11-08T15:45:48Z")

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The video seems to have expired, I’d like to see it. If you could repost it I would greatly appreciate it.