Aquarium safe rocks?

clawlan

Don't harass the sea turtles!
Dec 29, 2006
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Atlanta, GA
A local Tractor Supply like mom&pop place by my house sells various rocks and minerals in bulk. Most are in sizes far too large for an aquarium but there are 2 types that are cheap and in smaller aquarium friendly pieces. Problem is, I am not sure if they are aquarium safe. They are labeled as Silver Schist and Red Spar. Anybody ever heard of them?
 
No but you can test to see if the rocks are good by dipping or pouring some vinegar over the rocks to see if they fizz..if they do, that means the rocks are no good and can mess with your pH in your aquarium.
 
The Schist should aquarium safe. It's basically metamorphic sandstone.

The red spar - Im not sure of. It seems to be a local common name, not a scientific one. The only concern would be if it's some sort of mineral ore that could leach metals into the water. A local guy actually gave himself mercury poisoning by adding Cinnabar ( a pretty red rock) to his tank. The ammonia in the tank leached out mercury and formed an organic mercury compound in the water, wich can be absorbed through the skin.

The vinegar test is also usefull as it will ID limestone based rocks. They may affect your pH, in a good way if you have African cichlids, not so good if you have softwater fish.

Ian
 
...The only concern would be if it's some sort of mineral ore that could leach metals into the water...

Ian

Yea that's my main concern. As for the red spar, I have no idea what it is, though both the rocks I mentioned came from South Dakota.
 
Spar is a term to describe feldspar, so that is probably what you have. Feldspar is a silicate. It is used in stoneware glazes and is considered a foodsafe ingredient.

Some basic info on Feldspar http://encyclopedia.kids.net.au/page/fe/Feldspar

Feldspar is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earth's crust. They crystallize from magma in both intrusive and extrusive rocks; they occur as compact minerals, as veins, and are developed in many types of metamorphic rock. They may also be found in many types of sedimentary rock. This group of minerals consists of three silicates: a potassium-aluminium silicate (the orthoclase feldspars), a sodium-aluminium silicate, and a calcium-aluminium silicate (the plagioclase feldspars) and their isomorphous mixtures.

Any chemistry nerds have more input on this?
 
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