# is this slate rock?



## celaeno (Apr 28, 2006)

i got 25 of these mini boulders. they're supposed to be black slate, but there was fizzing when i did the acid test on a few rocks. come to think of it, doesn't slate usually come in flat tiles and slabs? heck, there even seems to be iron pyrite aka fool's gold on some pieces. what rock would you say this is if not slate?


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## danielratti (Feb 17, 2008)

granite


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## celaeno (Apr 28, 2006)

any idea how granite would fail the acid test?


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## SoDakJeep (Mar 21, 2009)

I have a granite tombstone in my tank but it is a differnt color. I am not sure how it would fail an acid test though I have never tried.


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## celaeno (Apr 28, 2006)

i just took some photos of two of the rocks.

some of them have one or more shiny surfaces:









most if not all have tiny reflective crystals:









and two even have fool's gold:









i hope this helps in id'ing the rocks.


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## danielratti (Feb 17, 2008)

Well fools gold will kill your fish. Any rocks that are shiny like that will produce toxins.


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## willny1 (Nov 17, 2008)

The top picture you posted is of Limestone. People seek limestone to put in their aquariums. It helps buffer the Ph to keep in a range at or above 7.6

You will mostly see this in aquariums with people who have African rift lake setups.

The second picture you posted I would not put in your tank. It appears to have pyrite. Which can cause many adverse effects in your tank.

The tiny reflective crystals on the rocks you have are a type of sandstone.


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