🔎 UNIDENTIFIED Got a few interesting gem/rocks

[iLikeRocksMN]

Along the way amateur agate hunting I find a lot of interesting rocks. I’m still amateur but developing an eye for the LSA’s

Stare at these quite often but here’s just a couple I’m wondering about:

no matter how much I research it appears I’m unable to figure out what these are using pictures as a guide, so any help would be appreciated. May be poor description but hopefully you get the jist of it!

Item #1 the huge gap in middle with all the darkness inside-appears to be a Crystal of sort but on outside dense and waxy. Blue/white/yellow

Item #2 the larger, less bumpy one with the thick dark bluish lines running all around

Item#3 similar to 2 but smaller with more bumpy exterior and has more of a gray color thin lines (pic with magnifying glass)

Item#4 flatter circular one with red patch on the side, has dark red and yellow “noodles” running within

 

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[fuss]

They are Chert nodules, we have an abundance of them here in Wisconsin as well. Formed in Limestone, some can be semi translucent and have partial banding. Many have cavities that can be filled with tiny Quartz crystals.

 

[iLikeRocksMN]

They are Chert nodules, we have an abundance of them here in Wisconsin as well. Formed in Limestone, some can be semi translucent and have partial banding. Many have cavities that can be filled with tiny Quartz crystals.

Thank you for the clarification as it makes sense to me now! Do you think these worth cutting and polishing ? I have one or two that are translucent with some pretty banding visible from the outside

 

[ToddsPoint]

If you have a diamond saw you should try them. Many types of chert are fine grained enough to take a high polish. Having bands or color is a big plus.

 

[VickyRenee]

Along the way amateur agate hunting I find a lot of interesting rocks. I’m still amateur but developing an eye for the LSA’s

Stare at these quite often but here’s just a couple I’m wondering about:

no matter how much I research it appears I’m unable to figure out what these are using pictures as a guide, so any help would be appreciated. May be poor description but hopefully you get the jist of it!

Item #1 the huge gap in middle with all the darkness inside-appears to be a Crystal of sort but on outside dense and waxy. Blue/white/yellow

Item #2 the larger, less bumpy one with the thick dark bluish lines running all around

Item#3 similar to 2 but smaller with more bumpy exterior and has more of a gray color thin lines (pic with magnifying glass)

Item#4 flatter circular one with red patch on the side, has dark red and yellow “noodles” running within

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That's not chert, there's no way.
That has a more quartz chalcedony appearance.
I am a huge LSA hunter, and I search the Grand River and go to different areas all along northwest Missouri.
I find these all the time and I know what you mean on trying to figure them out LOL!
I've got a lot I'm still staring and wondering at LMAO.
But actually I have a few I've been working on in cleaning. I use a dremel and it works wonders.
A few of these pics reminds me of the crazy lace agates I'm cleaning.
I use the grinding stone bits and it's taking off the layers of outer rock and exposing these BEAUTIFUL bands!
Try this yourself on some!

 

[Clay Diggins]

That's not chert, there's no way.
That has a more quartz chalcedony appearance.

Chert is Chalcedony.

https://www.mindat.org/min-960.html

Agate, Jasper, Flint, Chert and a lot more rocks are all chalcedony of different colors.
All the same mineral. We just call it by different names depending on our culture, the appearance and location.

 

[VickyRenee]

Chert is Chalcedony.

https://www.mindat.org/min-960.html

Agate, Jasper, Flint, Chert and a lot more rocks are all chalcedony of different colors.
All the same mineral. We just call it by different names depending on our culture, the appearance and location.

Well, yes, they are, but chert is made of the microcrystalline part of quartz making it a sedimentary rock and chalcedony is the micro fibrous form of quartz making it a mineral.
There's a difference.

 

[Clay Diggins]

Well, yes, they are, but chert is made of the microcrystalline part of quartz making it a sedimentary rock and chalcedony is the micro fibrous form of quartz making it a mineral.
There's a difference.

It's an interesting concept. New to me. I've never seen that distinction. Could you share your sources?

Chert is mostly microcrystalline quartz, as are most chalcedony. I've never heard of chert (including flint) being exclusively microcrystalline or as only having a sedimentary origin although most chert is easily associated with some form of sedimentation. In any case it would be an odd distinction to make since the actual chemistry, physics and crystal forms of minerals are their defining characteristics - not their genesis. Quartz, including microcrystalline quartz can be found in abundance in igneous and metamorphic as well as sedimentary rocks.

Here are a few copy/paste from my previously posted source.

Cherts are tough, compact rocks with low porosity that are composed mainly of microcrystalline quartz and varying amounts of impurities (Folk et al 1952; Smith 1960). The quartz occurs as randomly interlocked, microscopic quartz grains (microquartz) or fibrous chalcedony (Folk et al 1952; Smith 1960; Oldershaw 1968; Knauth 1994).

Cherts in banded iron formations are thought to have formed from primarily chemically precipitated silica. Often they are colored brightly by co-precipitated iron minerals (Sugitani et al 1998; Rosière et al 2000; Maliva et al 2005; Fisher et al 2008).

Magadi-type cherts, named after their occurrence at Lake Magadi, Kenya, form by leaching of alkali ions from silicates in silica-rich evaporites (Hay 1968; Eugster 1969).

The term "chert" is occasionally also used for massive rocks made primarily of microcrystalline quartz that deposits around submarine volcanic hydrothermal vents ("black smokers"; Hopkinson et al 1999; Gutzmer et al 2001), or that formed as siliceous sinter, like Rhynie chert (Hesse 1989).

Of course this is all semantics. It's the same rock no matter what you or I prefer to call it. It's all just common quartz no matter the source or color.

In my experience a lot of these naming conventions are driven by cultural and financial interests playing on the visual differences to establish a monetary value for rocks that humans are attracted to. That's why a fine 50 gram piece of Chrysoprase can be worth thousands while in the same deposit opaque red Jasper has virtually no value. Both are Chalcedony from the same source but the visual difference and appeal determine the value.

 

[ArfieBoy]

Wow! Lots of information in these exchanges! Thanks everyone.

 

[VickyRenee]

It's an interesting concept. New to me. I've never seen that distinction. Could you share your sources?

Chert is mostly microcrystalline quartz, as are most chalcedony. I've never heard of chert (including flint) being exclusively microcrystalline or as only having a sedimentary origin although most chert is easily associated with some form of sedimentation. In any case it would be an odd distinction to make since the actual chemistry, physics and crystal forms of minerals are their defining characteristics - not their genesis. Quartz, including microcrystalline quartz can be found in abundance in igneous and metamorphic as well as sedimentary rocks.

Here are a few copy/paste from my previously posted source.

Cherts are tough, compact rocks with low porosity that are composed mainly of microcrystalline quartz and varying amounts of impurities (Folk et al 1952; Smith 1960). The quartz occurs as randomly interlocked, microscopic quartz grains (microquartz) or fibrous chalcedony (Folk et al 1952; Smith 1960; Oldershaw 1968; Knauth 1994).

Cherts in banded iron formations are thought to have formed from primarily chemically precipitated silica. Often they are colored brightly by co-precipitated iron minerals (Sugitani et al 1998; Rosière et al 2000; Maliva et al 2005; Fisher et al 2008).

Magadi-type cherts, named after their occurrence at Lake Magadi, Kenya, form by leaching of alkali ions from silicates in silica-rich evaporites (Hay 1968; Eugster 1969).

The term "chert" is occasionally also used for massive rocks made primarily of microcrystalline quartz that deposits around submarine volcanic hydrothermal vents ("black smokers"; Hopkinson et al 1999; Gutzmer et al 2001), or that formed as siliceous sinter, like Rhynie chert (Hesse 1989).

Of course this is all semantics. It's the same rock no matter what you or I prefer to call it. It's all just common quartz no matter the source or color.

In my experience a lot of these naming conventions are driven by cultural and financial interests playing on the visual differences to establish a monetary value for rocks that humans are attracted to. That's why a fine 50 gram piece of Chrysoprase can be worth thousands while in the same deposit opaque red Jasper has virtually no value. Both are Chalcedony from the same source but the visual difference and appeal determine the value.

LOL, okay, it's fine, I actually wasn't looking to get this technical about it.
I didn't mean to say anyone was wrong, I just meant it doesn't look like the chert (and mozarkite) I know, and hence, your comment about different areas etc etc., which I get.

It's an interesting concept. New to me. I've never seen that distinction. Could you share your sources?

Chert is mostly microcrystalline quartz, as are most chalcedony. I've never heard of chert (including flint) being exclusively microcrystalline or as only having a sedimentary origin although most chert is easily associated with some form of sedimentation. In any case it would be an odd distinction to make since the actual chemistry, physics and crystal forms of minerals are their defining characteristics - not their genesis. Quartz, including microcrystalline quartz can be found in abundance in igneous and metamorphic as well as sedimentary rocks.

Here are a few copy/paste from my previously posted source.

Cherts are tough, compact rocks with low porosity that are composed mainly of microcrystalline quartz and varying amounts of impurities (Folk et al 1952; Smith 1960). The quartz occurs as randomly interlocked, microscopic quartz grains (microquartz) or fibrous chalcedony (Folk et al 1952; Smith 1960; Oldershaw 1968; Knauth 1994).

Cherts in banded iron formations are thought to have formed from primarily chemically precipitated silica. Often they are colored brightly by co-precipitated iron minerals (Sugitani et al 1998; Rosière et al 2000; Maliva et al 2005; Fisher et al 2008).

Magadi-type cherts, named after their occurrence at Lake Magadi, Kenya, form by leaching of alkali ions from silicates in silica-rich evaporites (Hay 1968; Eugster 1969).

The term "chert" is occasionally also used for massive rocks made primarily of microcrystalline quartz that deposits around submarine volcanic hydrothermal vents ("black smokers"; Hopkinson et al 1999; Gutzmer et al 2001), or that formed as siliceous sinter, like Rhynie chert (Hesse 1989).

Of course this is all semantics. It's the same rock no matter what you or I prefer to call it. It's all just common quartz no matter the source or color.

In my experience a lot of these naming conventions are driven by cultural and financial interests playing on the visual differences to establish a monetary value for rocks that humans are attracted to. That's why a fine 50 gram piece of Chrysoprase can be worth thousands while in the same deposit opaque red Jasper has virtually no value. Both are Chalcedony from the same source but the visual difference and appeal determine the value.

It's an interesting concept. New to me. I've never seen that distinction. Could you share your sources?

Chert is mostly microcrystalline quartz, as are most chalcedony. I've never heard of chert (including flint) being exclusively microcrystalline or as only having a sedimentary origin although most chert is easily associated with some form of sedimentation. In any case it would be an odd distinction to make since the actual chemistry, physics and crystal forms of minerals are their defining characteristics - not their genesis. Quartz, including microcrystalline quartz can be found in abundance in igneous and metamorphic as well as sedimentary rocks.

Here are a few copy/paste from my previously posted source.

Cherts are tough, compact rocks with low porosity that are composed mainly of microcrystalline quartz and varying amounts of impurities (Folk et al 1952; Smith 1960). The quartz occurs as randomly interlocked, microscopic quartz grains (microquartz) or fibrous chalcedony (Folk et al 1952; Smith 1960; Oldershaw 1968; Knauth 1994).

Cherts in banded iron formations are thought to have formed from primarily chemically precipitated silica. Often they are colored brightly by co-precipitated iron minerals (Sugitani et al 1998; Rosière et al 2000; Maliva et al 2005; Fisher et al 2008).

Magadi-type cherts, named after their occurrence at Lake Magadi, Kenya, form by leaching of alkali ions from silicates in silica-rich evaporites (Hay 1968; Eugster 1969).

The term "chert" is occasionally also used for massive rocks made primarily of microcrystalline quartz that deposits around submarine volcanic hydrothermal vents ("black smokers"; Hopkinson et al 1999; Gutzmer et al 2001), or that formed as siliceous sinter, like Rhynie chert (Hesse 1989).

Of course this is all semantics. It's the same rock no matter what you or I prefer to call it. It's all just common quartz no matter the source or color.

In my experience a lot of these naming conventions are driven by cultural and financial interests playing on the visual differences to establish a monetary value for rocks that humans are attracted to. That's why a fine 50 gram piece of Chrysoprase can be worth thousands while in the same deposit opaque red Jasper has virtually no value. Both are Chalcedony from the same source but the visual difference and appeal determine the value.

LOL, okay, it's fine, I actually wasn't looking to get this technical about it.
I didn't mean to say anyone was wrong, I just meant it doesn't look like the chert I know, and hence, your comment about different areas etc etc., which I get.
It's not a big deal okay, sorry!

 

[Clay Diggins]

LOL, okay, it's fine, I actually wasn't looking to get this technical about it.
I didn't mean to say anyone was wrong, I just meant it doesn't look like the chert I know, and hence, your comment about different areas etc etc., which I get.
It's not a big deal okay, sorry!

No need to be sorry VickyRenee, you brought up an interesting concept. It's a forum, with some luck we sometimes get to discuss some interesting concepts. Thank you.

It's funny - the most valuable gems are the ones in sets with large sizes and perfect matching color and clarity. All the same. Then you look at chert (or flint or jasper depending on where you live) and each piece is unique, almost like a little world in itself. Makes me think maybe beauty is in the mind of the beholder.

 

[ToddsPoint]

We have no precious gems here in IL. We have to make do with what we have. Polished chert from So IL. This material came from an area with a lot of iron. Value: Not much!