A Limestone Rock

When I was in High School, I was ask by my teacher that'What rocks that chalks came from? I was then so embarrass with the question and in the very first place I really don't know. And apparently her question answer by himself also. And she said that chalks came from a rocks called 'Limestone' as the description of the rocks which composed of calcium carbonate.

When the first time I saw it its not actually totally white but there are lot's of forms and gestures of the stones, It doesn't means that the color of it were black it doesn't look limestone, When our teacher showed us to us were so very happy too. Its so smooth even though it has a marks in the sides of it. As you can see its very useful they also used it in many buildings and many establishments that made in limestone.

  It is a sedimentary rock composed largely of the minerals calcite and aragonite,
Like those  coral or foraminifera they had also compose of limestone. Limestone makes up about 10% of the total volume of all sedimentary rocks.






Limestone was also a very popular building block in the Middle Ages in the areas where it occurred, since it is hard, durable, and commonly occurs in easily accessible surface exposures. Many medieval churches and castles in Europe are made of limestone. Beer stone was a popular kind of limestone for medieval buildings in southern England.

And also the  Great Pyramid of Giza ,the outside cover of it, is made up of limestone.