05-06-2013, 05:08 PM
That's a lot of questions. I can answer a few...
Geologically, granite is a plutonic rock of a specific composition. About 5% or the "granite" sold as countertops is actual granite. The rest of it is a variety of plutonic and metamorphic rocks, with an occasional really hard sandstone thrown in there. "Granite" in the countertop business is really just a trade name for any really hard rock containing a large proportion of silicates. There are literally hundreds of different types, some of them amazingly beautiful. Go to a specialty granite slab purveyor and you will see that the selection they have at Lowes and HD are absolutely pathetic.
Most "granites" are somewhat porous. They are not as bad as marble or limestone, but they will stain. Most people seal their granite countertops every few months or years.
Cracking occurs when you have a badly done installation.
The problem with dual sinks is that they are often too small so that you can't fit your largest pots/pans/roasting dishes in them.
I very much doubt that a hot pot will cause granite to crack since it was formed at several thousand degrees.
Many types of granitic rocks offgas minute quantities of radon. There has been research on this that has found that most granite countertops emit no detectable radon, or insignificant amounts. However, there have been a few that have been found to emit enough to be a mild concern. You can get test kits for radon fairly cheaply. Also, your granite supplier may have data available. A bigger question is, do you get a higher dose of radioactivity from the countertop or from the bananas sitting on it (bananas contain a lot of potassium, which emits radiation upon decay of potassium 40) or from the offgassing of the rocks beneath your home into your basement? Here's an article on radon from countertops: http://www.snopes.com/medical/toxins/granite.asp
Geologically, granite is a plutonic rock of a specific composition. About 5% or the "granite" sold as countertops is actual granite. The rest of it is a variety of plutonic and metamorphic rocks, with an occasional really hard sandstone thrown in there. "Granite" in the countertop business is really just a trade name for any really hard rock containing a large proportion of silicates. There are literally hundreds of different types, some of them amazingly beautiful. Go to a specialty granite slab purveyor and you will see that the selection they have at Lowes and HD are absolutely pathetic.
Most "granites" are somewhat porous. They are not as bad as marble or limestone, but they will stain. Most people seal their granite countertops every few months or years.
Cracking occurs when you have a badly done installation.
The problem with dual sinks is that they are often too small so that you can't fit your largest pots/pans/roasting dishes in them.
I very much doubt that a hot pot will cause granite to crack since it was formed at several thousand degrees.
Many types of granitic rocks offgas minute quantities of radon. There has been research on this that has found that most granite countertops emit no detectable radon, or insignificant amounts. However, there have been a few that have been found to emit enough to be a mild concern. You can get test kits for radon fairly cheaply. Also, your granite supplier may have data available. A bigger question is, do you get a higher dose of radioactivity from the countertop or from the bananas sitting on it (bananas contain a lot of potassium, which emits radiation upon decay of potassium 40) or from the offgassing of the rocks beneath your home into your basement? Here's an article on radon from countertops: http://www.snopes.com/medical/toxins/granite.asp