Unknown rocks from SD/NE border

[Kjane79]

Just wondering if someone could tell me what these are? My grandparents found them somewhere around the SD/ NE border around the Black Hills/ Badlands area in the early 60s. I've always been curious as to if they are something special or not. I think they're beautiful.( The first photo is the same rock as the last 2 photos.)

 

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[vpnavy]

1st - I noticed this was your very first post - so, Welcome Aboard Kjane79!

2nd - I moved ya from WHAT IS IT? over to ROCKS/GEMS for more exposure.

 

[ANTIQUARIAN]

Welcome to Tnet from Toronto 'J'!
Very cool rock finds, hope you get the info you're looking for.

Dave

 

[Steve1236]

Hi, welcome to the forum, looks like Chalcedony/Agate, maybe jasper in pictures 4 and 11, what's what I'm pointing at, it gets blurry when I try to zoom in, maybe take a close up pic clear photo and I or someone with more knowledge will be able to help you better.

 

[Kjane79]

I think it's just dirt.

 

[Steve1236]

It's still blurry, pictures can be deceiving, looks like gold, pyrite or maybe limonite but not dirt, how does it look in person, gold metallic looking?

 

[DDancer]

I agree with Steve Agate/Chalcedony mix. As to the red one I'd call it agate however its mixed with something else and it looks like it has a course grain structure. The golden part reminds me of a pyrite but you say it looks like dirt so I'm inclined to think its a bit more quartz with a citrine coloration. It appears to have some structure to it but I cant make it out. Good picture under natural light would help. Nice collection glad you like them.

 

[Kjane79]

I accidentally broke part of my golden dirt off. It is very hard, if that tells you anything. Its not magnetic. I don't have any jeweler's acid to test on it. I've always assumed that gold nuggets were more metallic and shiny. Apparently I'd have made a terrible 49er.

 

[Kjane79]

Here's the other piece

 

[Steve1236]

My guess is limonite, DDancer is more knowledgeable though, let's see what he or someone else thinks...
I'm curious myself.

 

[Kjane79]

Limonite doesn't sound nearly as profitable as gold. But it definitely seems more in line with my luck.

 

[DDancer]

In your original pictures Kjane the lighting, likely the flash, made the golden part look metallic so we were questioning what we were seeing Thanks for the natural light and better pictures it helps. Unfortunately I cant make a determination on the golden material, I dont believe its limonite as Steve suggests, but it does appear to have similar silicate properties to the chalcedony is mated to. Its not metallic, so no gold or pyrite, but I feel its another mineral altogether different from the chalcedony with some sugar quartz mixed in. Still a nice piece. Most I can say from a picture.

 

[Moesia]

Zeolite most likely based on the description and the pictures.

 

[Clay Diggins]

Knowing that area of the country the odds are it's Travertine. Appearance is about right.

Quartz of any size is pretty rare in the prairie states. Most rock you will find is formed by water re deposition from solution (limestone = travertine) or evaporation. Bedrock is precambrian sedimentary limestone and mudstones and it's really deep under all those 1,000's of feet of the fine grassland loam.

It's possible this piece has both travertine (base rock) and an evaporite like dolomite (calcite replaced by magnesium through solution evaporation = dolomitization). The two rock types are closely related in composition and formation processes and both are fairly common in that area.

The yellow stuff could be a zeolite group mineral. A rather dangerous test is to see if the rock is anhydrous by licking it. If your tongue sticks to the rock it's probably anhydrous. (please don't lick rocks or eat wild mushrooms unless you are an expert) Or it could just as easily be calcium sulfate (gypsum). Gypsum forms under similar conditions as the other calcite based rocks being discussed here and sometimes is colored by impurities.

 

[Moesia]

As for chalcedony vs carbonate he should take an iron nail and see if it scratches the rock at some point, press hard Kjane.

When it comes to the yellow stuff which I was referring to, I don't think it is gypsum. Kjane mentioned in a post above that it is a hard material and gypsum is only 2 on the hardness. That aside, you can see in a second to last picture he posted when you zoom in, that it is made of small elongated interlocking crystals. That form is more common in zeolites than anything else. Something similar in form is to be seen in dolomite and ankerite crystals.

If that is the case he should be able to scratch the crystals to whit a nail. But that would not exclude zeolites as most zeolites can be scratched with a nail. The only way to know with some certainty is for Kjane to do an acid test, so if you Kjanu don't have any acid with you, maybe you have some vinegar? Try to warm it up a little if you have any before you spill a little over the minerals to see if they fizzle.

The yellow coloration is highly unusual and it resembles more road paint than anything else. The pictures are to blurry to tell anything for sure.

 

[Jon Stewart]

Don't know but that rock with the maroon color in could be a nice rock for knapping arrrowheads

 

[CatEyeSapphire]

These look like Smithsonite or smiths stone as my grandpa would call em. I know when you look it up you get all these bright lovely specimens but most pieces I've come across look a lot yours they have a dull blue/white/brown color. The other orange rock with stripes of white could be a number of things but my best guess is Agate It's hard to tell what else it could be from just a picture. As for the gold dirt looking stuff if it is a mineral the only thing I know that looks similar is Marcasite but sense it crumbled so easy It's more likely some sort of harden clay or dirt. Maybe try letting them soak in a tub of hot water for a few hours it should help get any loose dirt off.

 

[Kjane79]

I would have gotten back to everyone sooner, but ever since I licked that rock, time just gets away from me. (JK) Seriously, thanks for all the information and advice. I'll try the vinegar test out and report back if anything stellar happens.
Thanks again!
Kjane
Ps. I'm a girl