Mineral alignment in a metamorphic rock usually gives the rock a porphyritic texture.

Classified in Geology

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Loads of things are made of minerals. Rocks are a mixture of minerals and minerals are a mixture of chemical elements. Every mineral has properties. A mineral has the physical properties (you can see from the outside): colour, shape, size, shine, hardness, cleavage (how does the mineral break). And it also has the chemical properties (you can’t see from the outside): carbon dioxide…(minerals). Crystals can form from freezing and cooling, and we know that because the video shows us that if you mix sugar (or magnesium sulphate as we did in the lab which are crystals already) with hot water, and then we cool the water down we will obtain a bigger crystal. This process is called re-crystallization. The video also teaches us that diamond is the hardest mineral and that talc is the softest mineral. We can find minerals everywhere, rocks are almost everywhere and us, humans eat minerals found in food. Rocks are separated into 3 different types of rocks:

— Igneous rocks are formed when magma solidifies, they are going to be weak because it is going to form very quickly due to the vast change of temperature from the interior of the earth(volcano) to outside it.

— Sedimentary rocks are made from bones from animals or little rocks so, when sediments are mixed then layers are formed, and the younger sediments stay at the top.

— Metamorphic rocks are formed when heat and pressure change a rock into another type of rock, the new rock is a metamorphic rock. An example can be chalk which is made from limestone that is a sedimentary rock so, under a lot of heat and pressure (and a long time) chalk will become marble. But we can’t change a rock into a metamorphic one, it takes a lot of time.

The rock cycle is the series of changes in which rocks go through, because they are always changing, they change because of the forces of nature like for example, moving water and wind which move a lot of rocks until they break them so much that they become sediment an example of this could be the waves of a beach move back and force in the shore, breaking the rocks and for hundreds of years these rocks are broken down into pebbles forming sand, some of that sand will end at the bottom of the ocean and when placed under pressure (with a lot of time) will form sedimentary and more heat and pressure will change that sedimentary rock into a metamorphic one. Some rocks will sink enough into the earth to melt gain and that melted rock and that rock can come back up from a volcano as igneous rock do.

We have found loads of ways to use rocks for example, metamorphic rocks (marble) or igneous rocks (granite) to construct large buildings. And nowadays rocks are a very useful and necessary material for us.

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