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Rock ID Mysteries


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All of these are among finds I have kept from the past. They have been in a storage unit. I am fascinated with geology but have trouble ID'g rocks and don't like to smash em. This is a lot of pics ... maybe too many?! Thanks in advance for all who take a moment to share their expertise. Much regards! 

 

 

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^ is this part of a thunderegg?

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^ the shell of the rock above (part of a thunderegg?)

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^ could this be a thunderegg or just jasper?

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^ a pyrite next to my thumb, is the middle rock a chalcopyrite?

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^ shell of the rock pictured below

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^ assume this is a banded agate?

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^ could it be a geode? 

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^ not a great pic -- this coloration is actually light to deep purple/ violet

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^ heavy, as if a cannonball, damn near perfectly round

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^ also heavy nearly round rocks

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^ sunstone? found in a creek north of the Arctic Circle

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^ can't even guess ... looks like a vein within a vein, what could that material be?

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^ nature couldn't create such an indent, could it? 

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^ same stone as above ... is this a relic of sorts? 

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^ same stone as above

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^ could this have been a spear head? 

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^ might this be a corondum? 

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^ same rock as above; what are those inclusions -- jasper? can't be rubies.. 

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^ same as above

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^ what happens when your 3 year old daughter finds your rocks! 

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Hey Mac

I am a pretty novice rock collector, so no expert.  The first few labelled thundereggs? look like chert, a type of fine grain quartz common up there, flint is a type of chert and has that fracture pattern.

The round rocks could be geodes, I thought that’s what they call thundereggs up here.  I think if you place them in water and they feel lighter, they may be a geode with an air pocket.  

Rather than smash them, you can cut those small ones carefully in half with a tile saw.  Go slow and use lots of water or some rock shops will cut them for $5 or so.

If you are referring to the internal corner indent, I would guess that is a natural fracture.  In that one though, the reverse view almost looks like a notch shaped into it near the base and the curved indent near your thumb could be worn by rope or something if it was lashed. Maybe?

The spearpoint doesn’t look like the right type of rock to me, chert was used often for arrowheads/spears points because it fractures nicely and leaves sharp edges.  In the Brooks Range I have seen ancient evidence of natives chipping chert for knives or spearpoints.  You’ll find piles of chipped rock that was carried to a spot with a overview or lookout of the land,  the chipped rock doesn’t match any of the natural rock.  Can just picture an old hunter chipping spear points waiting for game to move through. 

No idea on the others but that orange polished one is beautiful. Neat rock up there, we did a trip several years ago, amazing colors in some of them. If you head that way again, there is a Alaska Rockhounding book with a lot of good info and sites in it. If you are in Anchorage the folks at Nature’s Jewels Rock Shop on Arctic are friendly folks.

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On 8/13/2018 at 11:54 PM, Sasquatch said:

novice rock collector, so no expert

Well, more an expert than myself! I value your assessments and much appreciate the above knowledge/ ideas. Very cool those may be geodes. I will certainly do as suggested. Great idea to use my tile cutter for rocks! As for chert spears, I have photos of that very thing as well, along the Denali Hwy in the eskers is evidence of a boulder of chert showing where spears were calved off, yes pretty cool. Brooks Range, now that is where some serious gold lies ... oh how I'd love to know someone who lives in Nolan! That rock shop on Arctic, ya I forgot about them ... that is where I need to go when in town next. Thanks again Sasquatch.   

P.S. I was hopeful it was a thunderegg lol, those are more elusive than gold nuggets. I have read geodes are crystal filled and thundereggs are solid inside; star shaped patterns with jasper at the edges and agate in the middle. But I really don't know

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I always thought they were the same but had to google it, you're right thundereggs are solid and geodes hollow, never knew that.  A friend was given an uncut geode and I took it in there, they sliced it but that's all it was, a tile saw, moving slow with lots of water.  Would take a good bit of polishing to shine them up, but they can do that also, cost depends on size and time it takes to polish. Better than smashing with a sledge hammer to see what's inside.

The banded one does look like an agate, some are more translucent than others.

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First two : Chalcedony interior and exterior views, waxy luster and melted wax like look on the outside.
third : chalcedony again
fourth : certainly looks like chalcopyrite but could be arsenopyrite, try scratching it on some porcelain and check
for the smell of sulfur~ burnt matches
Fifth and sixth:  Not sure, the rind of the stone is decomposed; maybe host rock; and the interior shows layering.  Agates don't decompose
like this and the interior does not show the luster common to agate however it does appear to be a quartz mineral.

As to the round stones Sasquatch's idea with a tile saw is a good one however geodes are not generally noticeable in water by weight.  Your sunstone is pretty nice but I cant really say what it is though its attractive ?  The green and red stone towards the end of your thread looks like blood stone, heliotrope, and here again a tile saw might be helpful to cut a slab and polish it a bit.  I don't see any indications for corundum or garnet in the mix.  It looks like a jasper mix to me.  Hardness test would help.

All in all a good little collection.  My thoughts.

 

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