Geology/is granite as decorative rock hazardous for human?
sir i have a question is that radon which is one of a series of elements formed by the radioactive decay of uranium is hazardous for human and cause cancer and it concentrates in two abundant rocks, granite and shale and we often use granite to decorate our houses so i want to know is using granite as decorative rock not hazardous ???
and my second question is that Why does no mineral exist with the composition Si03 ? thanks
The small amount of radon generated from decorative granite is not a concern. What started the fears is homes built in or on areas underlain by large granite batholiths. A mass of granite that is say 20 square kilometers or more in size generates a lot of radon. The fear is that this radon will leak into homes sitting above it, and concentrate in the homes, exposing the people living their to high concentrations of the gas.
A counter top is not going to do anything.
I have counter tops, end tables, and coffee tables made of granite.
Another thing to consider is that not all stone called "granite" by those providing the decorative stone is actually true granite.
For instance there is no real black granite. What they call granite is really gabbro, a coarse grained version of basalt.
All rocks are named scientifically by their mineral composition. We look at a piece of the rock cut very thin under a microscope and identify the minerals therein. Base on the percent of each mineral type, we consult a chart and plot the percentages and where they fall within a "field" on the chart determines what kind of rock it is scientifically.
Then the grain size also is an added variable. The same rock as granite, if it is very fine grained is called a rhyolite. If it has certain accessory minerals in it, it might end up being classified as a Biotite Granite for example. Most granites are about 60% Feldspar, 30% Quartz and 10% Iron Manganese minerals.
White "granite" is usually a form of Andesite. It is named after the Andes where it is common. It is the white with black flecks "granite" but is of a different mineral makeup.
Diabase, and Gabbro account for a lot of the other "green" granites. and so it goes.
The granites with all the alignments, swirls and bands are not granite either, but intermediate igneous rocks, somewhere between igneous and metamorphic rocks. In other words they have undergone change due to pressure and temperature during mountain building resulting in the original rock being mangled and mashed. So they are not true igneous granitic rocks either.