Stone

> == == > == ==  Stone is a construction material mostly used for building purposes. These structures have existed as long as history recalls and have been considered a valuable and essential part of the building industry. The first famous structure ever built with stone was Stonehenge, which nowadays is located in the United Kingdom and is composed by a circular setting of large standing stones. There are many kinds of stones with different characteristics and chemical compositions that provide them particular properties that determine their use. For example, granite, chalk, coal... although there're three main kinds of rocks that help us to classify the others, and they are igneous rock, sedimentary rocks and metamorphic rocks. Stone is a long-lasting material and a very dense one. All the possible and multifaceted uses generate a high demand for this resource, and in the last decades new technologies have led to considerable advances in the excavation and further processing of natural building stones.
 *  ** What are stones? **
 *  ** How many kinds of stone do you know? **
 *  ** What characteristics do stones have? **
 *  ** Why are stones used in construction? **

BRAIN MAP ANALYSIS:
==Stone, like any other construction material, has advantages and disadvantages. Some of its advantages are: 1) it's a long-lasting material and preserves very well through time, 2) it's very moldable for scultural purposes, 3) it's used naturally, since most of the rocks don't need much processing. On the other hand, some of the disadvantages are: 1) since it is a very heavy and dense material, it's difficult to cut and transport it, 2) it's not flexible (it means that when we try to stretch the rock in two opposite directions it doesn't become longer either in the lateral or the vertical direction), 3) depending on the kind of rock, some of them might be more expensive than others, 4) it's a delicate material when it comes to maintain balance between more than two structures.==

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