Can granite be used to cultivate live rock?

[loonz]

Thanks for any inputs, and if not, what kind of rocks can be used for aquaculture. How is limestone rock different from granite?Or are they the same?Thanks again.

 

[MattM]

Ahh, Rockhounding! One of my other hobbies...

Limestone is a monomineralic rock (i.e. it's mostly just one mineral) consisting of 95% to 100% Calcite. The other (up to) 5% can be Dolomite, Siderite, Quartz, Feldspar, Mica, Clay, Limonite, Hematite, Glauconite, or Chlorite. Calcite is CaCO3, in other words, Calcium Carbonate. FYI, the second most common CaCO3 mineral after Calcite is Aragonite. So Limestone would make a good base rock for aquaculture.

Granite is actually a family of rocks including about 20 different varieties. The constituent minerals are:

20% to 60% Quartz
40% to 80% Feldspar
0% to 20% dark minerals including Biotite Mica, Muscovite Mica, Augite, Hornblende, Apatite, Zircon, and Magnetite.

Quartz is SiO2 (Silicon Dioxide).

Feldspar has a variety of compositions, but most are some mix of K[AlSi3O8] (Potassium Aluminum Silicate), Na[AlSiO8] (Sodium Aluminum Silicate), and Ca[AlSiO8] (Calcium Aluminum Silicate).

The most common dark minerals are Biotite and Muscovite Mice which are K(Mg,Fe)3[(OH,F)2AlSi3O10] and KAl2[(OH,F)2AlSi3O10], respectively (I won't try to convert those to chemical names ).

So with all that Silicon and other metallic elements, Granite would make a poor choice to put in your tank.

 

[madrefkepr]

Granite would also be a poor choice because it is not very porous, and therefore has much less surface area for bacteria to grow on.

 

[loonz]

thanks for the response, so what kind of rocks would you recommend?

 

[MattM]

Tufa or Limestone.

 

[Anonymous]

I'd strongly suggest you stay away from metamorphic rock, as well as any kind of volcanic rock. Save yourself the trouble and buy good South Pacific live rock.

 

[Anonymous]

He's in Singapore, so his question may have a different meaning than for us. But yeah, limestone or mined coral rock would be best.

 

[Bob Gardner]

I'd stay away from tufa if I was you. It's easy to work with a saw when aquascaping but therein lies its problem. It's easy to saw because its soft and due to that it crumbles easily and you will end up with a clogging layer of fine tufa scum on the bottom of the tank or blocking up your gravel/sand if you have any. This happened to me a long time ago and it took me a lot of work to gradualy rmove it and replace it with real live rock which cannot be bettered IMO.
Bob

 

[royy]

I use rocks from carib-sea. They are called reef-rock. You can get 50lbs from thatpetplace.com for $50 including the shipping. They are not a pourous as live rock, but they are made from old coral reefs that are now above ground. They do have some openings in them. As far as looks, I can't distinguish them from the real live rock I have since the coraline encrusted them.

Roy

 

[MattM]

I'd stay away from tufa if I was you.

Crumbley Tufa can be a problem, but there are lots of variations in Tufa depending on where it's from. It is formed in alkaline lakes that have calcium rich hot-springs feeding them. Calcium carbonate Tufa forms where the lake water meets the hot-spring water. Because of the wide varition of minerals that may be present in the hot spring, there are lots of variations of Tufa.

The stuff we get from Feller Stone in Utah is pretty hard - there is some dust when you break or cut it, but no further breakdown after that. Once it gets coralline covered, you could never tell it was once Tufa. I know of another company in Canada that sells Tufa for landscaping, but it is rich in metallic elements that you wouldn't want in your tank. It's possible that the Tufa Bob had was more delicate or soluable than most.

 

[Anonymous]

I would STRONGLY suggest staying as far away from volcanic/metamorphic rock as you possibly can.