Normanskill chert

[pkfrey]

I am helping a friend of mine from NY identify some of the cherts he's finding. One of the most frequent he's finding is Normanskill chert. We all know that chert and flint are found in a large variety of colors, and the colors are due to mineral inclusions that combined with the silica to produce the chert. My question is, does anyone know what the background mineral would be to create the greens, blacks, and even blue, Normanskill chert. For example, in Pa., we know that jasper has a high iron content that is responsible for the yellows, browns, and red colors. What makes the variety of colors in Normanskill? Thanks in advance if anyone knows. I can't find it in any of my mineral reference books. I was thinking magnesium, serpentine, or olivine, but I don't know for sure.

[sailorjoe]

Hi Paul. In the chert formations in the southeast one can find cherts of various colors from almost white to black with all shades between. I see no reason as to why that could not be the situation with the formation that produced the Normanskill chert. As to the mineral that could impart the colors that concern your friend it seems like a good geologist could provide that info. As to what was going on back eons ago to make that happen that would or could be a very complex story. So the bottom line is. Sorry that I can't help you on this puzzle. But if you find the answer I would like to know what you found out.

[Hoss]

Paul there is a short paragraph on Normanskill in this report. http://www.donaldprothero.com/files/47440292.pdf Not sure if it helps.

[pkfrey]

Thanks Hoss, I read the report, very lengthy and you have to understand a lot of big words used when studying geology. But I got through it, and the answer was there. The color has pretty much to do with metamorphosed chlorite minerals associated with different degrees of natural heat caused by varying degrees of pressure. Thanks Hoss and SJ, Your time is very appreciated.

[Ron Kelley]

Hey Paul, I just read this and found it very interesting. Everyone is familiar with the black-top roads throughout the world. Well in the U.P. we have a lot of red roads and many green roads. The red roads are because iron ore tailings were used and the green roads are because copper ore tailings were used.

[Tam]

Paul , you are in the right track . I find blue chert but it’s so rare . I have been studying the minerals and Chert deposits till my head hurts . It’s all about the density and what minerals were able to deposit in the rock as you stated . I know you goggled the top ten blue minerals but Joe is on to what a geologist would know . The density of your Chert on a chart with the area and what took place . What minerals could deposit in it .
I also did read that the Early Archaic and Paloe NA seemed to have these cherts but not all in your area .
Not the answer you are looking for but al least you.can help your friend with a mineral chart .

[pkfrey]

Thanks Tam, This is a never ending study when it comes to determining how certain lithics were formed, and the deposition of certain other minerals that will change the colors. But it's all part of research and what collectors NEED to do, in order to stay away from all the fakes and crap on the market.

[Tam]

Well if I don’t find it in the dirt or on top of it that’s my little circle ... They sure have some nice ones on EBay but you never know . I did find a a relatively inexpensive testing kit . Think I am going to invest in a microscope .

[pkfrey]

Tam, You " think " your going to buy a microscope? That would be the greatest investment you could make right now. I've had a scope for about 20 years, and i wouldn't collect without it. Once you have it, it takes just a little while to learn what to look for, what artifacts should look like, and what they shouldn't look like. What you see under a scope vs. naked eye is another world! With all the fakes and crap on the market, I would say using my scope, for myself and others, has saved me in the thousands of dollars, by identifying fake pieces. By all means, get a scope. I use one place, Am scope. You can find them on the net. They have very reasonable prices, and all you need is a student scope with 4 powers and a light from the top.
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