Thundereggs

[lissa318]

I received 46 Richardson Ranch thundereggs of various sizes im the mail today!!! Excited about trying something new. . I will be cutting them and polishing the worthy ones. They look pretty promising to me! Is there a sign to tell the best direction to cut and a friend of mine offered to lend me her tile tile saw... Not sure if it would work for the smaller ones? Advice appreciated and I will add pics as I go along.

Edited November 14, 2014 by lissa318

[lissa318]

Love the texture and designs on many of these. Pretty cool just as they are...

[rejd]

I have cut a few of those on my tile saw and it worked pretty good. As for the orientation I was told there is no real way to know. Just cut and hope for the best. Can't wait to see what you get from those. keep us posted.

[tmaier]

For those of you who don't know what thundereggs are...

http://en.wikipedia.org/wiki/Thunderegg

http://www.google.com/search?q=thundereggs&btnG=Search&hl=en&gbv=1&tbm=isch

I didn't know, and had to look it up. I thought it was about more dinosaur eggs.

[lissa318]

I have cut a few of those on my tile saw and it worked pretty good. As for the orientation I was told there is no real way to know. Just cut and hope for the best. Can't wait to see what you get from those. keep us posted.

Thanks appreciate it! Good to know about the tile saw. Some of them are fairly small and would be nice not to have to cut them all in the class I take. I pay for it and would rather polish there! If the tile saw wasn't a great option I would not use it though. The orientation worries me. I hate to ruin a nice one cutting it the wrong way... :/

[lissa318]

For those of you who don't know what thundereggs are...

http://en.wikipedia.org/wiki/Thunderegg

http://www.google.com/search?q=thundereggs&btnG=Search&hl=en&gbv=1&tbm=isch

I didn't know, and had to look it up. I thought it was about more dinosaur eggs.

These AREN'T dino eggs?!?!?! UGGGHHHH. LOL.

[rejd]

I don't think you can ruin them by cutting them the 'wrong' way. I believe they will turn out nice regardless of how you cut them. Good luck.

[lissa318]

I don't think you can ruin them by cutting them the 'wrong' way. I believe they will turn out nice regardless of how you cut them. Good luck.

Reassuring to hear!!! These are a first for me so thanks.

[PaleoRon]

I find that they display better if cut through the long axis.

[Herb]

whichever way you cut them make sure they are held securely on the saw. You wouldn't want them launched like a meteorite.

Good luck and look forward to seeing the results.

Saw expert ,7 fingers Jones, is looking forward to seeing the pix also.

[Herb]

Oooh,that was just mean!

[painshill]

There is some helpful advice given here which relates to observation of the flow-banding and other features on the exterior of the nodules (which you may or may not be able to see):

http://www.zianet.com/geodekid/howtocut.htm

Good luck Lissa.

[old dead things]

I have a very limited experience with thunder eggs and geodes as far a cutting them is concerned. Years ago at an auction in Yuma, Arizona I picked up several buckets of each and they traveled to Wyoming with me a few years later and of course they ended up in the same bucket and I didn't know which was which.

I have an eight inch Highland Park Rock trim saw, which means I can cut a four inch rock. I have to admit it was a lot of fun and realized that about half way through I knew if I had a geode or a thunder egg. The geodes had mud or dirt that turned to mud from the rock saw oil and once I saw the mud it was extra exciting to finish the cut. It was probably wrong, but I pushed them through with my fingers (yes I still have them all).

The hardest part of cutting a thunder egg or geode is the polishing. I never could get a smooth cut using the hand method, so it took and extra amount of time on the lap polisher to grind them to a smooth finish. I've been asked many times how to tell a geode from a thunder egg and honestly I can't tell the difference, but was once told, " if you find a semi-round rock that looks like it had a nervous break down, it is probably a geode."

Jim

Edited November 14, 2014 by old dead things

[lissa318]

whichever way you cut them make sure they are held securely on the saw. You wouldn't want them launched like a meteorite.

Good luck and look forward to seeing the results.

Saw expert ,7 fingers Jones, is looking forward to seeing the pix also.

There is some helpful advice given here which relates to observation of the flow-banding and other features on the exterior of the nodules (which you may or may not be able to see):

http://www.zianet.com/geodekid/howtocut.htm

Good luck Lissa.

Herb, coming out with all 10 digits and not launching any are both on my checklist of this being a successful learning experience... hahaha!

Painshill, that is wonderful info!!! Thank you! I checked a couple on the top of my box and some do have very obvious pressure ridges like this one.

I'm not seeing banding on few I looked at but I'll be inspecting them all when I have time. Thanks again!

Edited November 14, 2014 by lissa318

[lissa318]

I have a very limited experience with thunder eggs and geodes as far a cutting them is concerned. Years ago at an auction in Yuma, Arizona I picked up several buckets of each and they traveled to Wyoming with me a few years later and of course they ended up in the same bucket and I didn't know which was which.

I have an eight inch Highland Park Rock trim saw, which means I can cut a four inch rock. I have to admit it was a lot of fun and realized that about half way through I knew if I had a geode or a thunder egg. The geodes had mud or dirt that turned to mud from the rock saw oil and once I saw the mud it was extra exciting to finish the cut. It was probably wrong, but I pushed them through with my fingers (yes I still have them all).

The hardest part of cutting a thunder egg or geode is the polishing. I never could get a smooth cut using the hand method, so it took and extra amount of time on the lap polisher to grind them to a smooth finish. I've been asked many times how to tell a geode from a thunder egg and honestly I can't tell the difference, but was once told, " if you find a semi-round rock that looks like it had a nervous break down, it is probably a geode."

Jim

Thanks for sharing your personal experience with me! I am now wondering if it wouldn't be better just to use the saw at my class since there's a clamp I can use. Might save time in the long run with the grinding and polishing!!! And the "semi round rock that looks like it had a nervous break down" description cracked me up! They sure do look like that... hahaha. This one intrigues me. Has the pressure ridges but quite different than the others. I can't wait so see what's in it!

Edited November 14, 2014 by lissa318

[Plantguy]

That looks like fun! I remember seeing piles of them cut/uncut in the rock shop. The polished ones were amazing in their variety.

I also heard stories that I know were embellished about a few rock launches while being cut...They were serious stories but very funny! I think its kind of along the lines of getting a new dog and putting em in the fenced enclosed backyard thinking if you leave it alone it will behave and not dig or somehow end up in the neighbor's yard messing with their cat or running down the street chasing children.

Be Safe. Show us the fabulous insides! Regards, Chris

[old dead things]

Lissa,

I'd be tempted to not cut the one that looks like it has an ammonite on top, a very unique piece, but if I did cut it, I'd save the swirls. Almost looks like a didymoceras on top, wow. I can tell you are going to have fun.

Jim

[Herb]

I wouldn't cut that one either, it looks pretty cool as is.

[Ludwigia]

I understand that the difference between a geode and a thunderegg is that basically a geode has a hollow with crystals in it in the middle and a thunderegg has a solid filled center. You can find agate or other minerals in both types. I spent a lot of time cutting and polishing geodes and agate nodules back when I was collecting minerals and really enjoyed the sometimes surprisingly colorful and beautifully intricate patterns which magically appeared once they were sliced. That always made up for the occasional dud which inevitably cropped up. You never know what you're going to get and that's what makes the process so exciting. Have fun!

PS. If I was given the choice, I'd cut that last one the way Jim suggested, You can always place the two halves back together and then play peekaboo...

Edited November 14, 2014 by Ludwigia

[Herb]

"Thunder eggs" are formed in volcanic ashes. Geodes are mainly just rocks with holes in them, often filled with crystals; usually formed in sedimentary strata.

[painshill]

"Thunder eggs" are formed in volcanic ashes. Geodes are mainly just rocks with holes in them, often filled with crystals; usually formed in sedimentary strata.

Yep... quite right Herb... I was just typing this off-line:

Strictly speaking, “geode” is a generic for a resistant mineral (usually chalcedony) which independently formed as a hollow shell. Usually, it’s crystal lined (but doesn’t have to be) or filled. It can be so infilled that to all intents and purposes it’s a solid mass, but nevertheless still composed of a shell and an interior. Because they can be formed in so many different ways and with so many different mineral interiors, it’s usual to qualify the name according to shape, origin or mineralogy.

But geode and thunderegg are not synonymous. Thundereggs are formed by a specific geological process (which is not well understood) but probably arising in cavities and vesicles in rhyolitic lava flows and/or hot ash layers before solidification. They may or may not have a shell (if they do, it’s composed of adhering silicified host rock) which is concentric in form but the interior often exhibits sedimentary layering in the manner of an agate. The primary composition is usually chalcedony which has been fractured by deposition of quartz (crystalline, cryptocrystalline or amorphous) as any combination of crystalline quartz, agate, jasper or opal. Gypsum is also possible, plus various secondary minerals – and that’s what gives them such interesting internal colours and patterns.

A thunderegg could legitimately be called a geode if it had a hollow shell structure – so some thundereggs are also geodes, but not all geodes can legitimately be called thundereggs.

Some people use the term “lithophysa” which refers to similar thunderegg-like structures found in any felsic volcanic rock (which would include rhyolites).

[lissa318]

Wow thanks for all the great feedback and info everyone!!! It's appreciated. I will be taking a few to my lapidary class in the morning so stay tuned... lol. Hopefully it will be day 1 of NO launches. With 46 of these I decided to save the interesting one until the end. I really do like it as is. It may have to remain a big "?".

Edited November 15, 2014 by lissa318

[ynot]

Lissa,

Some further information on the formation of "thunder-eggs".

As a thick silica rich magma is rising to the surface, if the temperature is right, the silica will form nodular balls that have gasses within the structure. As the external pressure is decreased the gasses expand. If the temperature is in the right range the silica ball will "pop" (thunder-eggs). If the magma is a little hotter the gasses form a bubble ( Mexican geodes ). This provides the cavity for later mineralization. As the lava is extruded the ones near the surfaces of the flow will be broken and distorted, while the lava in the center of the flow holds them together. The interior composition is dependent on the minerals in and around the lava and the agents that move it to the voids.

Good luck with Your beauties

Tony

[lissa318]

Lissa,

Some further information on the formation of "thunder-eggs".

As a thick silica rich magma is rising to the surface, if the temperature is right, the silica will form nodular balls that have gasses within the structure. As the external pressure is decreased the gasses expand. If the temperature is in the right range the silica ball will "pop" (thunder-eggs). If the magma is a little hotter the gasses form a bubble ( Mexican geodes ). This provides the cavity for later mineralization. As the lava is extruded the ones near the surfaces of the flow will be broken and distorted, while the lava in the center of the flow holds them together. The interior composition is dependent on the minerals in and around the lava and the agents that move it to the voids.

Good luck with Your beauties

Tony

That was a very visual description Tony!!! I could picture it all in my head while I was reading. Great explanation! Thanks!!! Edited November 15, 2014 by lissa318

[lissa318]

Oh my goodness. I'm in love!!! Only cut 7 of the 46 and I already want more... I didn't have one dud today although the grinding and polishing did take a lot longer than I expected. I finished one half and have 3 more halves ready for the final polish. Here's the half that is finished!

I had issues with chipping on the edges which I don't think I can do much about if I want a good polish?

Quite a few had blue. Here's some different ones...

I was super excited about this one. The only geode so far.

Hard to get a good pic of this next one. Lots of lines and moss... Wish the bottom wasn't broken although it does stand by itself! lol

Picture in next comment...