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Chert compared to flint

PostPosted: Mar 2, 2015 7:11 am
by caver.adam
Here's a question for you all. If common chert is low quality flint, does that mean I can use chert and steel to make sparks to start a fire? It will be a while till I have a chance to try it so I thought I would ask.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 8:37 am
by graveleye
chert and "flint" are essentially the same rock. You can definitely make a spark with chert. Native Americans often made their points from chert.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 10:13 am
by GroundquestMSA
I recorded a video of my brother hammering on a rocky squeeze covered in chert nodules. Sparks are flying everywhere.
I have been confused by the terms chert and flint (spellchecker doesn't believe in chert). It's obvious that they are both forms of the same thing, but I don't know if the names are interchangeable.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 10:48 am
by caver.adam
Online research indicates that the difference between common chert and flint is related to the quality of the rock for use in tools.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 10:59 am
by GroundquestMSA
So it's all chert, but flint is "tool-grade" chert?

Re: Chert compared to flint

PostPosted: Mar 2, 2015 2:12 pm
by caver.adam
I'm hoping someone can either confirm or correct that.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 4:22 pm
by graveleye
this is one of those ambiguous areas of geology. Both rocks are the same in composition, essentially being micro-crystalline quartz(ite). The difference as I understand it is basically the color, and how it is found. Flint being found in nodules separate from the host limestone, chert being embedded in it.
I'm not a geologist, but from looking around, it's easy to see that geologists themselves haggle over the difference and sameness.
[url]
http://www.mindat.org/forum.php?read,7,207246,207985 [/url]
[url]
http://www.quartzpage.de/flint.html[/url]

Interestingly, I always referred to cave chert as "chert" since it is dark, and the red/gold/white stuff as flint... they all say it is the other way around.
Whatever. I have points I have found in south Georgia that are red and white and was always called "flint". I have points from N Georgia, Al and Tennessee that are dark that they call "flint" too, although it looks and feels just like the chert we see in caves.

It's the same stuff though, and will make sparks and tools if you know what you're doing.

Re: Chert compared to flint

PostPosted: Mar 2, 2015 4:23 pm
by graveleye
GroundquestMSA wrote:So it's all chert, but flint is "tool-grade" chert?


Oh, you can make tools out of all of it, in a nutshell.

Re: Chert compared to flint

PostPosted: Mar 5, 2015 10:32 pm
by Larry E. Matthews
In my experience, flint generally refers to gray, dark grey, to black rock that has a conchoidial fracture and is generally glossy.

Chert, even though it is the same chemically, usually is browns yellows, or white and may be slightly porous and is usually not glossy.

Both were used extensively to make stone tools.

Larry E. Matthews
Professional Geologist