Stone


 * STONES! **

**What are stones?** Stones are also called rocks, are accumulations of minerals in a very solid form. Are very important in geology because through them the geologist can know about how long is the earth.

I know three types of stones, talking in geologic terms.  Igneous: are formed by the volcanic magma. Sedimentary: are formed by the solidification of other rock's materials, and other minerals. Metamorphic: are formed by the alteration of their solid state, they are on the top of the land and are vulnerable to the nature's changes.  It depends of the rock’s type, but mostly the rocks are: strong, rigid, and resistant
 * How many kinds of stone do you know ? **
 * What characteristics do stones have?**

Mostly because its resistance and durability but also because some types of stones are beautiful and the are selected according to the architectural design
 * Why are stones used in construction?**

Stones are hard and solid mass formed by mineral substances. constructions with rock has a lot of advantages, like durability, a simple maintenance, easy for structural treatment and the high level of thermal inertia (capacity to absorb and conserve the warmness). Another point in pro for the use of the rocks, is the low level of environment impact that they make in their use. However, there are bad points in the uses of rock structures, the use of rock retard the constructions for the difficulty of the transportation, besides could generate accumulation of moisture. From the beginning of time, the humans have used the rock like a good construction material, for example we have Stonehenge in Great Britain, the great wall of China, castles in the medieval ages, Byzantines churches and even today in some houses..

media type="file" key="piedra 1.mp3"


 * 2 definitions in the text: **

"The entablatures (the upper sections of a classical order that rest on the capital of a column) of an ancient Greek temple"

"ashlar masonry, which consists of regularly cut blocks"


 * 2 statements of comparison and contrast:**

"Because of its weight and the precision with which it can be shaped, stone masonry (in contrast with brick) does not depend on strong bonding for stability where it supports only direct downward loads."

"The entablatures (the upper sections of a classical order that rest on the capital of a column) of an ancient Greek temple, for example, were bonded by small bronze dowels. But the weight creates problems of stability when loads push at an angle; stone vaults and arches require more support and buttressing than equivalent forms in other materials."


 * 2 statements expressing cause and effect: **

"and in some styles stone slabs are employed even for roofing (ancient Egyptian temples, early Christian basilicas in Syria). But this roofing requires so many columns that unvaulted masonry buildings are almost always combined with floors and covering in wood."

"The entablatures (the upper sections of a classical order that rest on the capital of a column) of an ancient Greek temple, for example, were bonded by small bronze dowels. But the weight creates problems of stability when loads push at an angle; stone vaults and arches require more support and buttressing than equivalent forms in other materials."


 * 2 adjectives in the superlative form, and 2 in the comparative form:**

Comparative form: More efficient - Most suitable

Superlative form: Strongest - Cheapest