# Blue-green rocks, name?



## FrostyNYC (Nov 5, 2007)

Its really hard to tell from that photo. 

It's possible they're just dyed that color. A LFS near me sells lacerock dyed green and blue. You could try scratching one to see if its actually green the entire way through.


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## jaidexl (Sep 18, 2006)

Can't say whether the color is natural or not, but they look like granite to me. It ranges in color depending on mineralogy so I guess green could be possible.


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## jaidexl (Sep 18, 2006)

Googled green granite and there is indeed plenty of it.


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## Hilde (May 19, 2008)

Thank you!! 

Found that granite is made up of 
Quartz --------- grey transparent
potassium------ feldspar alkaline white, pink, blue or non
Mica------------- brown, black
Crystal ----------white black seperate and big 2 to 5 mm
basalk 
Gattro

Now I am wondering if it will raise the ph in my tank which is 7.4 to 8.2.
Perhaps letting it sit in a bucket of tank water will tell me the results


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## jaidexl (Sep 18, 2006)

I've never heard of granite effecting pH, hardness or alkalinity


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## demosthenes (Aug 23, 2008)

Hilde said:


> Now I am wondering if it will raise the ph in my tank which is 7.4 to 8.2.
> Perhaps letting it sit in a bucket of tank water will tell me the results


no, it will raise it to precisely 8.3472. haha its hard to telll if itll change the pH or not unless you try it. if i were you, i'd get a pH test kit, put the rocks in a bucket of water and test the pH over the course of a few days or weeks.


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## Hilde (May 19, 2008)

Granite contains
quartz which is grey transparent
potassium feldspar alkaline which is white, pink, blue 

Mica brown which is black
basalk Gattro


What ratios differs per rock. Thus can only tell if it affect ph by testing it.


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## jaidexl (Sep 18, 2006)

Found this through a quick google - "Water becomes hard by dissolving soluble salts from the rocks or soil over or through which it flows. Some rocks, for example slate, granite, gneiss and schist, contain little or no soluble material and, as such, have a negligible effect." - then there was one site that suggested to stay away from it, that's the first time I've ever heard that, in contrast to the norm, so it goes on the list of many web pages I'll ignore from now on. 

Quickest way to tell is scrape the surface and drip some hydrochloric or acetic acid from a liquid nitrate or nitrite test kit and see if it sizzles.


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## Hilde (May 19, 2008)

jaidexl said:


> Found Some rocks, for example slate, granite, gneiss and schist, contain little or no soluble material and, as such, have a negligible effect." - then there was one site that suggested to stay away from it.


This makes sense to me for granite is made of several types of rock and it vary per rock.



jaidexl said:


> Quickest way to tell is scrape the surface and drip acetic acid from a liquid nitrate test kit and see if it sizzles.


This only show if it has carbonates, like limestone, correct? Granite can also contain potassium feldspar alkaline which makes me think it could raise the ph. If it only slightly does adding sodium bicarbonate should help. 

​


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## jaidexl (Sep 18, 2006)

Well, I'm no chemist and that's venturing into areas I'm not that strong in, but as far as I know, hydrochloric acid reacts to calcium carbonate and magnesium, as well as carbonate and bicarbonate. Which ones cause the bulk of the fizz I don't know, a lot of us already know what bicarb does in acid. . I just consider a pass on the fizz test as aquarium safe. I'm sure any 'negligible' or slow reactions will be made truly negligible by routine water changes.

edited typos


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## Hilde (May 19, 2008)

jaidexl said:


> hydrochloric acid reacts to calcium carbonate and magnesium, as well as carbonate and bicarbonate.


So basically if anything leaches that will affect the water chemistry it will cause a fizzing when acid is dropped onto the rock? 

I was concerned for read that the granite has potassium feldspar alkaline in it.


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## Left C (Nov 15, 2003)

Hi Hilde

Do your rocks look like any of these? 

Green Rhyolite









Pyrophyllite









Rhyolite









Felcite









I have seen tons and tons of green rocks that look similar to yours. There is a very old and eroded mountain range near me. It is the Uwharrie Mountains found in the Uwharrie National Forest. According to geologists, the Uwharries were created from an ancient chain of volcanoes. The 1,000-foot hills of today were once 20,000-foot peaks like the Rocky Mountains. They were formed around 500 million years ago when North Carolina was near South America. This is the one of the oldest mountain ranges in North America. Within this mountain range is a very complex geological formation named the Carolina Slate Belt. It extends from Virginia through North and South Carolina and into Georgia. You are in Mapleton, Georgia and your rocks could of been collected from this belt area. I'm in Burlington, NC and I'm in the belt too.










"The Carolina Slate Belt is a 10- to 50-km-wide zone of 450- to 600-million-year-old volcanic and sedimentary rocks extending from Georgia to Virginia (fig. 1). Acid-rich waters in volcanic centers locally altered the bedrock and deposited gold and silver and valuable minerals such as pyrophyllite (an important refractory mineral which can be a green color). Such deposits have been exploited at many localities in the slate belt. Regional mineral and geoenvironmental resource assessments depend on understanding the geology and the potential for undiscovered deposits -- challenging questions in the Carolina slate belt because of the complex geology, deep weathering of the bedrock, and dense vegetation cover over much of the area."
http://rla.unc.edu/Publications/pdf/ResRep25/Ch2.pdf

Another green rock found in the region is Rhyolite. Felsite is also found.
http://www.archaeology.ncdcr.gov/uwharrie/daniel26am.html
http://www.archaeology.ncdcr.gov/uwharrie/hibbard26am.html

The green rocks that I've seen may or may not be some of the above. The ones that I've seen were found near one of the lakes formed from the Yadkin River which passes through the Uwharries. I'll call the Ranger Station Monday and ask them what they are.


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## Hilde (May 19, 2008)

Left C said:


> Pyrophyllite


They look similar to this one. There were part of an ornament that I bought from someone on Ebay in New York.



Left C said:


> I'll call the Ranger Station Monday and ask them what they are.


That is necessary. Thank you!


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## Left C (Nov 15, 2003)

Do you see Kim Basinger around town? I used to go to Road Atlanta a lot.


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## Hilde (May 19, 2008)

Left C said:


> Do you see Kim Basinger around town? I used to go to Road Atlanta a lot.


Yeh, I think I saw her in a grocery store at 1 time and didn't say anything. What does this have to do with the rock?


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## MemphisBob (May 2, 2007)

Just that Kim rocks, or at least used to.


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## Hilde (May 19, 2008)

That is funny!!:hihi:


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## Fat Man (Nov 2, 2006)

I really can't see the pic's but could it be serpentine? In which case I'd be leary of putting it in your tank.


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## Hilde (May 19, 2008)

I am pretty certain the rock are granite.


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## Vladdy (May 6, 2008)

I can't really tell what kind of rock that is from the pics, but check out this article I made, it has some good info about the rocks: http://www.theaquariumwiki.com/Aquascaping


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## DorianBrytestar (May 26, 2009)

Hilde, I was up in Helen this weekend and we stopped and did some of the "gem panning" for kicks. I snagged a few rocks that look very similar to those and the guy there said they were Quartz. Take it with a grain of salt, but just to give you one more possibility.

(BTW, I just image googled "green quartz" and that looks real close to what you have)


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## metageologist (Jan 10, 2008)

Vladdy said:


> I can't really tell what kind of rock that is from the pics, but check out this article I made, it has some good info about the rocks: http://www.theaquariumwiki.com/Aquascaping[/quote]
> 
> 
> hey i read you article and one thing that you need to include is that when i comes to granite you must know its locality of origin or you can be introducing heavy metals in to your tank.
> ...


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## Hilde (May 19, 2008)

I have major plans for my aquarium. Problems with allergies and sinus infection are delaying me. 

I am planning to make a big hill, 7" high 10" long, and put the green rocks on top at the end.


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