Introduction
In geology, stone or rock is naturally occurring solid aggregate of minerals.
Stones can be either artificial stone or
natural stone. Stone masonry is similar in concept to brick/block masonry. Both
involve the stacking of preformed units and bonded in mortar.
The lithosphere, the Earth’s outer solid
layer is made of stone. In general, there are three types of stones, namely
igneous, sedimentary and metamorphic. The scientific study of stones is called
petrology. Petrology is an essential component of geology.
The compositions in stones are generally
classified by minerals and chemical, by the texture of the constituent
particles and by the processes that formed them. Stones can be separated by
these indicators into three types: igneous, sedimentary and metamorphic. Then,
they are further classified according to particle size. The transformation of
one stone type to another is called the rock cycle.
The rock cycle.
Rock cycle.
Igneous stone
Sedimenary stones
Metamorphic stones
The three classes of stones – the
igneous, the sedimentary and the metamorphic – are subdivided into many groups.
However, there are no hard and fast boundaries between allied stones. The
distinctive structures also of one kind of stone may often be traced gradually
merging into those of another by increase or decrease in the proportions of
their constituent minerals they pass by every gradation into one another.
Hence, the definitions adopted in establishing stone classification only
correspond to selected points (more or less random) in a continuously graduated
series.
The use of stones has had a huge impact
on the cultural and technological development of the human race. Stones have
been started to use by humans and other hominids for more than 2 million years.
The mining of rocks for their metal ore content has been one of the most
important factors of human advancement, which has progressed at different rates
in different places in part because of the kind of metals available from the
rocks of a region.
The prehistory and history of
civilization is classified into the Stone Age, Bronze Age and Iron Age.
Although the Stone Age has ended virtually everywhere, stones continue to be
used to construct buildings and infrastructure. When so used, rocks are called
dimension stone.
There are various types of stones.
Falkland palace, Fife (NTS). Different types of stones function within these structure.
Types of Stones
The Three Types of Rock
Igneous
Stones
When molten magma cools, igneous stones
are formed and are can be divided into two main categories: plutonic rock and
volcanic. Plutonic or intrusive stones result when magma cools and crystallizes
slowly within the Earth’s crust. For example, granite is onw kind of the stone
formed when the magma cools down. On the other hand, volcanic or extrusive
stones formed from magma reaching the surface either as lava or fragmental
ejecta such as pumice and basalt.
Igneous rock from the volvanic.
Process of formation of igneous stone.
Sedimentary
Stones
Sedimentary stones are formed by
deposition of either clastic sediments, organic matter or chemical precipitates
(evaporates), followed by compaction of the particulate matter and cementation
during diagnosis. Sedimentary rocks form at or near the Earth’s surface. Mud
rocks consist of mudstone, shale and siltstone comprise 65%; sandstone 20 to
25% and carbonate rocks which consist of limestone and dolostone constitute 10
to 15%.
The reddish-brown, swirly rock is ribbon chert. This hard sedimentary stone started or in the Pacific as deep-sea clay full of the microscopic shells of radiolarians, lying on the volcanic rock of the seafloor. It was once flat beds, but as the seafloor was subducted beneath California the chart was crumpled into a picturesque state.
A collection of terraced sedimentary stone in Somewhere Over the Rainbow.
The reddish-brown, swirly rock is ribbon chert. This hard sedimentary stone started or in the Pacific as deep-sea clay full of the microscopic shells of radiolarians, lying on the volcanic rock of the seafloor. It was once flat beds, but as the seafloor was subducted beneath California the chart was crumpled into a picturesque state.
You can click on it and has a look on the video.
Metamorphic
Stones
Metamorphic stones are formed by
subjecting any stone type which includes the previously formed metamorphic
stone to different temperature and pressure conditions than those in which the
original stone was formed. These temperatures and pressures are always higher
than those on the Earth’s surface and must be adequately high so as to change
the original minerals into other mineral types or else into other forms of the
same minerals. One of the processes is called recrystallization.
Slat is a metamorphic rock.
Metamorphic stone.
You can click on it and has a look on the video.
Earth’s
oldest stone formation
Depending on the latest research, the
oldest stone formation is either part of the Isua Greenstone Belt, Narryer
Gneiss Terrane or the Acasta Gneiss. The difficulty in assigning the title to
one particular block of gneiss is that the gneisses are all extremely deformed
and the oldest stone may be represented by only one streak of minerals in a
mylonite, representing a layer of sediment or an old dike. This may be
difficult to find. Hence the oldest dates yet resolved are as much generated by
luck I sampling as by understanding the stones themselves.
It is thus premature to claim that any
of these stones or indeed those other formations of early Archaean gneisses are
the oldest formations of stones on Earth; doubtless new analyses will continue
to change our conception of the structure and nature of these ancient
continental fragments.
Nevertheless, the oldest cratons on
Earth include the Kaapvaal craton, the Western Gneiss Terrane of the Yilgarn
craton (~2.9->3.2 Ga), the Pilbara Craton (~3.4 Ga), and portions of the
Canadian Shield (~2.4->3.6 Ga). Parts of the poorly studied Dharwar craton
in India are greater than 3.0 Ga. The oldest dated stones in Baltic Shield are
3.5 Ga old.
Oldest
stone on Earth
The Acosta Gneiss in the Canadian Shield in the Northwest Territories, Canada is composed of the Archaean igneous and gneissic core of ancient mountain chains that have been exposed in a glacial peneplain. Analyses of zircons from a felsic orthogenesis with presumed granitic protolithic returned an age of 4.031 ± 0.003 Ga.
On
September 25, 2008, researchers from McGill University, Carnegie Institution
for Science and UQAM announced that a rock formation, the Nuvvuagittuq
greenstone belt, exposed on the eastern shore of Hudson Bay in northern Quebec
had a Sm-Nd age for extraction from the mantle of 4.28 billion years. However,
according to Simon Wilde of the Institute for Geoscience Research in Australia,
it is argued that the actual age of formation of this stone, as opposed to the
extraction of its magma from the mantle, is likely closer to 3.8 billion years.
The oldest ground-edge stone tool in the world has been discovered in Northern Australia by a Monash University researcher and a team of international experts.
This Wrapped in EarthTM hoodie image is from Akilia Island, Greenland, which is locared in a cluster of islands about 15 miles southwest of Greenland's capital, Nuuk. The dark greenstone in this striking formation is 3.8 billion years old, making it among the oldest stone in the world. Akilia Island and Greenland share a violent history.
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