# what type of rocks are these?



## pharrix (May 26, 2011)




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## DanniGirl (Jan 25, 2007)

Looks like volcanic (igneous). If it has gas bubbles then it's basalt.


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## JimA (Nov 7, 2009)

They might have some iron in them kinda hard to tell. I do like the shapes of them though!


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## pharrix (May 26, 2011)

thanks for the replies.


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## S14Swap240sx (Jan 3, 2011)

DanniGirl said:


> Looks like volcanic (igneous). If it has gas bubbles then it's basalt.


is something such as volcanic rock sutible for a typical peacock hap tank?


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## DanniGirl (Jan 25, 2007)

Depends what type of volcanic rock. There are four types, basalt being the most common. The rougher the texture, the more problematic it could be for the fish. With that said, a few pieces wouldn't be an issue in a peacock/hap setup.


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## Mike_G (Nov 8, 2011)

I think a little clarification may be warranted here.
Igneous (volcanic) rock is one of the 4 types of rocks (igneous, metamorphic, sedimentary, and specific)- there are two main types of igneous rock, intrusive and extrusive, but there are several different varieties of igneous rock including (but not limited to) basalt, granite, pumice, andesite, rhyolite, obsidian, and scoria (aka "lava rock")

I'd try to stick with granite and basalt, and would avoid pumice (too soft), scoria (too rough), and obsidian (too sharp)

Just my .02


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## cichlid-gal (Apr 27, 2012)

here's a link (hope this works as I've not used this option before) to help with identification of igneous rocks and there is even a little test at the bottom of the page with pics of different types....my basalt looks like the basalt in pic/test #1

http://facweb.bhc.edu/academics/science/harwoodr/geol101/labs/igneous/

Nice looking :thumb: layout


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