What is the difference between chalk and marble

Chalk, limestone and marble are all examples of calcium carbonate aren't they? So what is the distinction between them? I don't think so. Calcium carbonate does have at least two crystal forms aragonite and calcite , but I think limestone, chalk and marble are all calcite. I think the difference is due to particle size, how well formed the crystals are and what impurities are present. Marble has much larger crystals than either of the other minerals. Chalk is formed in a deep marine environment from the shells of microscopic algae which flourish near the surface, but die and fall to the seafloor.

The kind of chalk used in old-style classrooms and lecture theatres scrapes off a thin layer of fine white dust as they are scraped over the abrasive surface of a "blackboard". Things like bones and teeth and shells are generally made of this amazing stuff, and when the critter dies, the calcium carbonate is returned to the earth for recycling into new and wondrous forms.

There are many types of creatures on earth, and quite a few of them at least by the sheer number of individuals are composed of a single living cell. There are quite a few different types of these primitive life forms. Many live in the ocean, and some extract calcium carbonate from the seawater to make a protective shell. The correct answer is Calcium carbonate. Important Points Calcium carbonate and its forms: In nature, calcium carbonate occurs in the forms of chalk, limestone, and marble.

Over millions of years, layer build-up and pressure from the top layer changes the bottom layer into chalk. Earth movements due to earthquake lift the layer of chalk to the Earth's surface. The earth's movements can also cause the layers to sink further. Thus, high pressure and heat cause the chalk to turn into much harder limestone.

The limestone deposit may stay below the Earth for a longer time and due to higher pressure and temperature, the limestone turns to marble.

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