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Post by fernwood on Sept 21, 2016 17:40:09 GMT -5
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Post by orrum on Sept 21, 2016 20:06:58 GMT -5
A experienced rockhound once told me the difference.....chert is plain Jane colors, while jasper has pretty colors. Who knows but I dont. Chert knapps well and so does jasper Both need to be cooked first.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 21, 2016 22:46:28 GMT -5
*L* We've been so round and round about this. This is the problem with common name terms. Some folks use chert for blah non colorful chalcedony or jasper. Some folks use jasper as a term for all opaque fibrous mineral included chalcedony.
In science, back in the dinosaur times when in was in school, chert was the name give to microcrystalline quartz of sedimentary origin. The amorphous silica in chert was derived from overlaying deposits of skeletons of critters so was of organic origin. Flint was essentially the common name given to chert nodules in chalk beds. Both can often contain included fossils. Ie Mozarkite, Flint Ridge, Mary Ellen etc.
Jasper, on the other hand was opaque or mostly opaque chalcedony associated with igneous deposits and the silica was from inorganic sources like volcanic ash etc. Ie Lavic Jasper, Bruneau Jasper etc which has formed or eroded from igneous deposits.
Chemically, they are much the same except maybe for the inclusions, as jasper is heavily included and fibrous but without fossils.
Far as the rockhound hobby is concerned though, this is all pretty meaningless due to common names, as many cherts are called jaspers and many things called jasper are neither chert or jasper....Mel
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Deleted
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Post by Deleted on Sept 21, 2016 23:39:55 GMT -5
Sabre52Don Kasper (a private researcher in Palmdale, CA) has defined Agate as chalcedony with less than 5% iron and jasper with greater than 5% iron. But, you are 100% correct. Common names in usage break all the rules. Making the rules meaningless.
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Post by orrum on Sept 22, 2016 8:10:00 GMT -5
Rule breaker, mean misery maker!!! LOL
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Post by fernwood on Sept 22, 2016 21:56:42 GMT -5
WEll, thanks for all the great info. Once again, my knowledge base has been expanded. Have come to the conclusion I am calling it Chert/Jasper. Have some rocks I know are jasper. Others that are more like chert.
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Post by tandl on Nov 4, 2016 15:13:30 GMT -5
Dont forget about flint . Cherflinasper
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Deleted
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Post by Deleted on Nov 4, 2016 15:17:56 GMT -5
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Post by Peruano on Nov 5, 2016 7:31:31 GMT -5
Sorry to be redundant but the Quartzpage web site is so thorough and can provide much thought provoking info, I need to point us all to it again. www.quartzpage.de/flint.htmlMel did a good job explaining the difference but the bottom line is its hard to tell the origin of a rock that has been transported by a glacier to a new spot. Shotgunner has a point - some of those rocks are outside the boundary of cherts or jaspers. Can you find at least one absolutely smooth spot on the rock before (or after) you hit it with a hammer. If so it might be a cryptocrystalline quartz relative. If not - not likely.
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Post by adam on Nov 5, 2016 9:03:49 GMT -5
A couple look like they may be jasper, but the rest either chert or granite as shotgunner said. Most of them rocks do look quite coarse and grainy.
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