Sandstone
is a sedimentary rock that consists of grains between 1/16 millimeters
and 2 mm in size. This is the reason that sandstone does not signify
any specific mineral. When we talk about scientific composition,
sandstone is made up of quartz. It also consists of some other minerals
such as clays, hematite, feldspar, ilmenite and mica. All these
minerals add color and character to the quartz matrix. Sandstones with
large amounts of impurities are generally categorized into wacke or
graywacke.
Sandstone
originates from the space where sand is laid down and buried. This
usually happens offshore. However, you can also find desert dunes and
beaches leaving sandstone beds. You would not see sandstone containing
good amount of fossils due to the unfavorable environment for
preservation. The stone is available in warm colors and very durable.
Quartz
grains in sandstone are mixed together by a mixture of silica, calcium
carbonate or iron oxide. The presence of iron minerals makes this stone filled with tan and brown bands.
When deeply buried, this stone
becomes mobile due to the burial pressure and higher temperatures. The
grains stick together and the sandstones turn into metamorphic rocks.
Sandstone
can be defined as an arenaceous sedimentary rock that is made up of
quartz and feldspar. The stones vary in color and are available in a
variety of colors such as white, grey, red and yellow.
Sandstone
is very soft and easy to work with. This makes it very good choice for
building and paving material. Clastic in nature, these stones are
opposed to organic such as chalk or coal. These are a result of
cemented grains or some other mono-minerallic crystals under pressure.
The
sedimentation pressure grains out of river, lake or sea helps in the
formation of sandstone. If you want to analyze the characteristics of
sandstone, you should pay equal attention to the environment of
deposition.
The
main environments of deposition can be easily split between terrestrial
and sea groupings. Here are some of the typical groupings available
under this category.
a) Terrestrial environments: Rivers and Lakes
b) Sea environments: Turbidites, shoreface sands and details
There are several types of sandstones available for consumer use. These can be divided into the following groups:
a)Arkosic sandstones:
These possess a high amount of feldspar. The amount of feldspar here is about less than 25% of the stone.
b)Quartzose sandstones:
These
sandstones possess a higher amount of quartz inside them. The best
example of these sandstones is quartzite that has less than 90% of
quartz content.
c)Argillaceous sandstones:
This category is known for its significant fine grained element. One of the best examples of this sandstone is greywacke.
(cn-stonenet.com)