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GeneralA) High quality travenite question. B) And weathering of quartz and chalcedony

3rd Mar 2017 14:55 UTCMichael Harwell

Hi all , a quick question and then a comment with a possible question about how quickly quartz and ts outer minerals weathers once out in the open environment .

First, someone mentioned I might have had high quality tavenite in my wonderstone I posted last week.

I've noticed a lot of the sand stone weathers away leaving strips of this "possible" travenite.

Is travenite worth anything if it's not solid block. Would collecting strips and bits and pieces be worth my time?

Next, after collecting beach recycled pebble and rocks I am noticing the ones I leave on my deck basically melt/weather away. the outer crusts or even banding weather away quite quickly and leave a white or semi transparent quartz center. This can happen in a few months even with temps no higher than. 70 (air) the deck gets hotter. We had rain and a few freezing nights but I'm kind of surprised how quickly it occurs. Simply amazed how fast this occurs.

Lastly, I love the discussion on agates the past few days. I have so many questions concerning chaceldony. Banding and agates. Quite a confusing subject and I appreciate everyone's input.

3rd Mar 2017 15:05 UTCMichael Harwell

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3rd Mar 2017 15:52 UTCErik Vercammen Expert

Quartz doesn't weather, but the ciment between quartz grains will.

3rd Mar 2017 20:05 UTCBob Harman

MICHAEL, Your pictured examples might have some collector value. Any value is what someone might be willing to pay you to own what you now own. Collect a few more pieces and bring them to a local club meeting or upcoming rock show and see if anyone might be interested.

Large massive portions of this stone have value as dimension stone. If stable for long time periods, like marble or limestone, it can be used for building exteriors or landmarks or monuments etc etc. Around my town all the buildings are of Indiana limestone. Looking at those buildings built before 1900, you can see early evidence of acid rain etc weathering.


As to quartz/chalcedony weathering, as ERIK stated, quartz doesn't really weather. Every day we see outcrops which include quartz which may be many hundreds of millions of years old. Opened Indiana geodes, which are collected all the time are mid Mississippian in age. They are 325 - 425 million years old and still found quite fresh.

I cannot believe that you are finding beach pebbles that might have also been lying around for millions of years and when you bring them home they "melt/weather away" in just months. Something just does not add up. Are you sure you didn't bring home someone's half used sugar candy????

3rd Mar 2017 22:22 UTCGregg Little 🌟

Michael;


A). I am not familiar with the term travenite but that might not be surprising as lapidarists, gemologists and metaphysical folks often come up with many colourful (and non-scientific) names for various known rocks. The strips that would weather out of your sandstone would still be sandstone.


B). You did mention freezing conditions at night. With the sandstone probably being quite porous, water (rain?) would be readily absorbed and then the freeze-thaw cycle can easily crumble a porous stone. The bleaching effect could also be from the rain/snow as precipitation is naturally slightly acidic. The iron oxide cement holding the quartz grains together in the sandstone could leach out with repeated soakings then the stone would take on a paler hue and start crumbling.


Another thought; do you have pets? Pet urine is slightly acidic so if they like peeing on your rocks that could definitely bleach and leach out the cement holding the sand grains together.


Again nice liesegang rings. They show how mobile in solution the iron cement is.

3rd Mar 2017 23:21 UTCWayne Corwin

Michael


Where you get your slabs, how bad is the stone there weathering?

Some layers weathering worse than other layers?

3rd Mar 2017 23:33 UTCDonald Kasper

Ditto that.

4th Mar 2017 00:37 UTCLawrie Berthelsen (2)

You don't mean travertine, do you?

4th Mar 2017 01:08 UTCMatt Neuzil Expert

I would have to see a picture of this process of your stone "melting" away. If I recall from the beach collecting post, these are collected along the coast of california. You live a distance away from the coast that you have a freezing and thawing climate?


Here in the midwest we had temperatures in the 70s last friday and 30s the next day. Last night my area got 6 inches of snow. None of my yard rocks in years have melted away due to freeze and hot sun.


It is hard to tell when not holding one of these stones, but it looks to be some kind of mud rock. Maybe it is a argillaceous limestone. It looks like rock I see in ohio. I look at this rock and i see what look like chipped gray areas. Maybe they aren't. But those areas could be a fresh exposure of the piece and what I believe to be liesegang rings.

4th Mar 2017 11:30 UTCRalph S Bottrill 🌟 Manager

We have a lot of similar sandstone in Tasmania, including the Leisegang rings. It commonly contains bands with a lot of montmorillonite or other smectites, and can disintegrate very rapidly with wet/dry cycles, even when it looks quite solid when fresh.

4th Mar 2017 13:03 UTCWayne Corwin

Does it help to coat them Ralph?

4th Mar 2017 16:45 UTCGregg Little 🌟

The discussion has ranged through iron oxide cemented sandstone to clay-rich sandstone to mudstone to marlstone to mud-rich limestone to limestone (travertine). Possibly Michael could give us a little more detail like does it fizz in dilute HCl and if he dissolves/dis-aggregates a few small fragments in acid or water, what residue remains?

4th Mar 2017 23:42 UTCMichael Harwell

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These past rains really did a number on some ugly green or yellow rocks. Red shades. Ect....

I've noticed that the heat will change the colors quickly in the deck.

However, these I left out around Jan 12. It's march 4.

A few frosty nights. But lots lots lots a rain. Temps no higher than 70

It's more the clay type rocks that don't keep a shine. I'm very new to all this but I'm venturing to say the rocks with more silica or higher concentrations don't weather away like this. May fade in color but the ones with less silica seem to weather rather quickly. We do have a higher content if mercury in our air/fog.

Acid rains this past month?

I'm leaving these and a few others out. I won't move them and take pictures somewhat daily.

4th Mar 2017 23:44 UTCMichael Harwell

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4th Mar 2017 23:49 UTCMichael Harwell

Ralph, your right on. It happens very quickly. One night. My large one took a hit I left it out in the sun and forgot. The next afternoon it had already split up in different pieces on its own.

Need time with the acid test but lots of limestone in the mountains here.

I was thinking of spraying them with a coat of something as well???

5th Mar 2017 00:00 UTCGregg Little 🌟

Pebble in the lower left of photo #6966 appears to have a stylolite ( pressure solution feature) and usually occurs in limestone and dolostone but I have seen them in a few sandstones. Limestone does weather more quickly than sandstone but again we are talking about years. Mercury is rather benign on rocks but nasty on the observer.

5th Mar 2017 00:18 UTCMichael Harwell

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I love the color of this one when wet and lit up in the sun. Pretty boring dry. porous clay mixture in quartz? Not a lot , if any silica. . (Ameture remember).

I'll put it out and we can watch this one melt away pretty quickly. ( I'm guessing). Light rains hitting now with a cold front passing. and passing showers tomorrow. Probably get an inch plus by tomorrow night. Not the 29 inches we received in January alone. And in a week or two or month we shall see.

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Ps. I started noticing stones change color and shape when I first started rock hounding and was collecting big sur jade at willow creek. I found some nice pieces and enjoyed keeping my best one in my pocket. Low and behold it changed lighter. The darker green gave way to a more luminous milky white green. I've done all sorts of experiments with freezing it and putting it in the sun. Then freezing it with different watery concoctions while submerged. I still have a baking glass in my other freezer with a stash of jade and other rocks I put in there about 5 months ago.

5th Mar 2017 01:14 UTCMichael Harwell

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Wayne and Ralph, the pieces fall from a bluff. But over time many are buried. as Ralph said, one wet and dry cycle will erode the sandstone. And or leisegang rings.

But just outer layers. One could scrape the surface looking for interesting rings. They are heavy. The longer piece weighs about 35 pounds. So, what and which ones. Then one breaks.

I'm guessing the better pieces are buried. Sealed in from the harsh environment and tightly held together.

However, the pieces I'm showing here where found close to the top of the bluff. I haven't seen a wall of them. But I can find a lot of the grey materiel that is not sandstone. Overtime the sandstone weathers and leaves behind strips and pieces of it. Very Small fragments of ringed sandstone are present along with it. Someone said it was high quality something. What is the grey materiel?

Ralph, I'm sure what I've found is very similar to what you referenced. When I put the pictures on beach and stream colllecting it was correctly identified as "wonderstone".

However, can you explain leisegang rings and there connection to sandstone.

Why did I post it in beach and stream collecting? It is the outer edge of an ancient sea bed . Sand hills are left and the area is quite diverse. Very fine sand used in glass making is quarryed in another section of the sand hills. And, it's the kiddy section of this site. Lol. The daycare center......

So, is this leisegang ringed sandstone part of the sand and the processes of 12 million years ? Or is it coming from from the walls "holding" the sand hills.

One can find megdaolon teeth. I'm sure to find one soon.....:)
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Recent record breaking rains have completely altered the land revealing walls of sand dollars. Massive block. I guess I found the right elevation where they were left. But up behind or in the sand itself is the wonderstone?

5th Mar 2017 18:24 UTCMichael Harwell

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More woberstone and or leisegang rings with sandstone. Weighs about 100 pounds. I got it down about 600 feet and one mile before 30 percent of the end broke. Big bummer. But I still managed to get the rest back anther 3.5 miles to my car. Lots of sand dollars too.

Do leisegang rings have anything to do with the process of agate formation or the banding that occurs with agates and others?

Any leisegang experts out there? Ps......I found the source. But even with that I can see the eons and eons of tiny fragmented remains all over. So??? Let's say I found fresh - er stones.

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5th Mar 2017 18:35 UTCMichael Harwell

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I found it like this. With a few light brushes and tugs I scraped off the front side. Attempted to get home whole. Oh boy am I sore......

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9th Apr 2017 15:17 UTCMichael Harwell

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Erik, I believe you are are right on, the cement ect...will weather faster. In my case it's weathering in months sometimes weeks.

From my observations. Weathering occurs at different rates. Initially when a stone lime these is finally exposed to air cold heat sun ect...the cement ect will weather quickly. Some of these cements hav color. After the initial weathering the rest of the material like quartz and silica take your millions of years ect....

I have a picture with me...not at home but vacation. Most of the rocks weather into this. It could be completely translucent or transparent. Yellow or white. Could have a white frosting covers the clear translucency. I'll post those pics later. But I'm finding all sorts of partially weathered stones and then the ones I have at home are doing it. I'll show the pics of rocks I laid out a few weeks ago. They have " melted". Revealing shells and one is revealing a pink rock/ mineral.

But, what is the core of these.

Silica?

I thought when I collected these early on the were a moonstone of sorts. Then quartz but now it's a silica of sorts........? How can I tell what kind of silica or concentrations.

I'll try seeing if it scratches later. On vacation with wife and I can since her frustration with my " rock hounding" time away from her.........til later.

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