A few more pics from last weekend

[GaryMc]

Can anyone help me identify? Once again found in Vermilion County 

, Illinois. Thank you and sorry to be of trouble.

[KimTexan]

It’s no trouble. Everyone has to start at the beginning. It all starts with getting out there and picking up interesting looking stuff and starting to ask questions.

One of the main points of this forum is to help educate and enlighten and to be educated and enlightened.

I have seen a few of your other posts.

One key thing to learn about paleontology is it is about things that lived in the past and pretty much everything that lives has some kind of symmetry or if incomplete we look for a pattern or distinct shapes.

Being familiar with the anatomy or specific shapes of things is helpful. Even though the fossil may be ancient those distinctive characteristics it had in life generally still exist or they would not be identifiable.

 

So look at what you’ve collected and see if you see distinctive shapes with symmetry.

Granted at times fossils can be encased in matrix and so you kind of have to see past the matrix to see the fossil.

 

One thing that may help you is to find pictures of fossils found in the formation you hunt in. 

I haven't been following your posts. Do you know the formation you hunt in?

One think I notice about all of the rocks I see is they all appear to be from alluvial deposits. Stuff found in a water way that is tumbled and smoothed out. Most of it appears to be limestone and some flint. All are fairly worn down. So if there were fossils there, they likely have lost some or all of their distinguishing characteristics just from tumbling in the creek or river. 

 

One piece looks like what they call tobacco flint due to its color being similar to tobacco.

The brown piece in the center of your first pic appears to be flint some people call it chert, but that specially looks like flint to me. Flint is one of many types ochalcedony, a microcrystalline silica based mineral, generally with a Mohs hardness of around 7. So it doesn’t break down as easily as limestone would and get rounded as quickly when tumbled. 

Not many fossils are made of chalcedony and they don’t look anything like that piece. Petrified wood is a common fossil preserved in chalcedony, but not generally flint. Agate usually.

If you know the formation maybe we can help you find pics of common fossils in your area and possibly even better hunting spots where your odds of finding identifiable fossils will be better.

I don’t see any fossils among your rocks, but most of them I can’t zoom in on.

I’m not sure I was of any help, but I hope some of it was helpful in some way.

[Aurelius]

I think you need to have a think about why you continually post these rocks here. If you think you're being funny, you're really not. If you are being genuine, then I suggest you take some to a museum, but you need to be prepared for the fact that you might get some funny looks. I don't think you'd believe them anyway, given that you don't listen to the experts here. If you genuinely want to find fossils, then I'm sure there are some people here who know your area and would be able to offer some tips, but nobody is ever going to tell you that those rocks are fossils, because they aren't.

[ynot]

14 minutes ago, KimTexan said:

Flint is one of many types ochalcedony, a microcrystalline silica based mineral,

Flint (and chert) are not the same as chalcedony (agate). They are all cryptocrystalline quartz, but flint and chert will only form in sedimentary rock whereas agate will form in any type of rock but is more common in volcanic rock.

[KimTexan]

7 hours ago, ynot said:

Flint (and chert) are not the same as chalcedony (agate). They are all cryptocrystalline quartz, but flint and chert will only form in sedimentary rock whereas agate will form in any type of rock but is more common in volcanic rock.

I believe we have had this discussion on at least 2 other occasion, possibly more. It seems to keep coming back to the definition of chalcedony. 

How you define chalcedony seems to be different than how I define it. I’ve checked my book and other sources. I believe I use the term correctly.

I have been bewildered each time you bring this up. I can’t figure out what I’m missing or what point it is you’re trying to make. Maybe I am a bit dense or so set in my concept of it I can’t see outside the box to where you’re coming from.

 

Chalcedony is the term for all forms of quartz in cryptocrystalline form. 

There are many forms of chalcedony. Agate, avertine, carnelian, onyx, chert, flint to name a few. Some are sedimentary and some are not.

Flint is a specific form of chert. Flint can be called chert, but chert should not be called flint. I don’t use the terms interchangeably.

Flint and chert are forms of chalcedony based on how chalcedony is defined as the term for all forms of quartz in cryptocrystalline form. 

I’d like to understand what your point is, but I’m not sure I get it.

[FranzBernhard]

1 hour ago, KimTexan said:

I’m not sure I was of any help, but I hope some of it was helpful in some way.

What a great and educational post! Thanks, Kim!
Franz Bernhard

[Kane]

Likely worn sedimentary cobble deposited as post- or inter-glacial outwash, as is consistent with your area.

[DPS Ammonite]

 

6 hours ago, KimTexan said:

Chalcedony is the term for all forms of quartz in cryptocrystalline form. 

There are many forms of chalcedony. Agate, avertine, carnelian, onyx, chert, flint to name a few. Some are sedimentary and some are not.

Flint is a specific form of chert. Flint can be called chert, but chert should not be called flint. I don’t use the terms interchangeably.

Flint and chert are forms of chalcedony based on how chalcedony is defined as the term for all forms of quartz in cryptocrystalline form. 

I’d like to understand what your point is, but I’m not sure I get it.

In the geological community, chalcedony is not the name for all varieties of cryptocrystalline quartz. However, chalcedony occurs in many varieties of crypto and microcrystalline quartz rocks.

 

Kim, what book do you use for the definition of chalcedony, chert, jasper etc?

 

Definitions vary depending on the community the term is used in. Here is a standard definition used by geologists and found in the best geological glossary, Glossary of Geology by Bates and Jackson (1987): “A cryptocrystalline variety of quartz. It is commonly microscopically fibrous, may be translucent or semitransparent, and have a nearly waxlike luster...” 

 

Chalcedony is contained in chert and flint.

 

Chert often contains chalcedony, opal and other impurities. To geologists, chert includes flint and jasper.

 

 

 

 

 

 

 

 

 

 

 

 

 

[Pemphix]

Back to topic: there are just rocks, no fossils imo (by just judging from the blurry pics).

I would recommend to read a little bit - internet, books, articles, geological maps - to find out / to learn a little bit about fossils in general (how they are looking in general, where and in which rocks/stones/sediments they can be found and where not, if there are places nearby you where they can be found and how they're looking,..and so on).

(Continious) Reading is a big part of this hobby, which is necessary to understand, enlarge and update your knowledge.

You will see: the more you read, the more you know and the better you are able to "read in the million years old book of stones"    

Happy to see your efforts here in the forum

[ynot]

7 hours ago, KimTexan said:

It seems to keep coming back to the definition of chalcedony. 

From MINDAT.org....

 

Chalcedony

A variety of Quartz

Depending on the context, the term "chalcedony" has different meanings.

1. A more general term for all varieties of quartz that are made of microscopic or submicroscopic crystals, the so-called microcrystalline varieties of quartz. Examples are the different types of agate, jasper, chert, chrysoprase, onyx, pietersite, etc. 

 

 

2. In the strict sense, and in the scientific literature, "chalcedony" designates aggregates of parallelly grown ("fibrous") quartz crystals of microscopic and sub-microscopic size. Based on the conspicuous behaviour of thin sections of chalcedony in polarized light, at least two types can be distinguished (Michel-Lévy and Munier-Chalmas, 1892; Correns and Nagelschmidt, 1933; Braitsch, 1957; Frondel, 1978; Flörke et al. 1991):
- length-fast chalcedony, with crystallites stacked perpendicular to the c-axis, and the resulting fibers being elongated either along [1120] or -more rarely - along [1010]. The fibers may be twisted around the elongation axis.
- length-slow chalcedony or Quartzine, with crystallites stacked parallel to the c-axis, and the resulting fibers being elongated along [0001], like in macrocrystalline quartz.

Both types tend to develop radially grown "fibers", resulting in botryoidal, rounded and stalactitic habits. They often show concentric banding perpendicular to the fiber orientation and are then called Agate.
Length-fast chalcedony and quartzine may be found intergrown. The crystallites are commonly polysynthetically twinned by the Brazil law (Graetsch, 1994; Cady et al 1998; Xu et al 1998).
It is not possible to distinguish the types with the naked eye. Length-fast chalcedony is far more common than quartzine.

Aggregates of randomly intergrown microscopic grains are called "microquartz" (Flörke et al, 1991; Graetsch, 1994). The more general term explained under (1) includes length-slow and length-fast chalcedony as well as microquartz. 

Most chalcedony contains small amounts of the silica mineral Mogánite, usually between 1% and 20% (Heaney and Post, 1992). Aging slowly converts the mogánite into quartz and results in mogánite-free chalcedony (Moxon, 2004). 
Chalcedony contains small amounts of water, both as molecular water and bound in silanole (Si-OH) groups (Frondel, 1982). 


3. A term sometimes used for chalcedony that is not agate, jasper or another sub-variety. Used in particular for botryoidal specimens. 

 

 

So, dependent on which definition  used, We are both correct.

For more information on chert, flint and agate see this link-https://www.mindat.org/mesg-6-453145.html

[Fossildude19]

As there is nothing more to be gleaned from this topic, it has been locked.