Science Question Please Help?

Question

Why can two rocks look very different even though they are made of the same materials? Give and example.

Answer 1

Rocks are formed by the constant grinding of particles. Depending where the rocks were found, weather and erosion play a part in how they look. For example, rock A could be shaped one way due to the constant wind blowing East  which cause the rock to form an upward slant. Rock B could be in the path of a stream or shifting river which becomes grinded and shaped by other rocks tumbling over it which will obvioulsy cause a different shape to the rock.

Answer 2

Well, they can be different because of the way they form. Let's take, for example, obsidian and pumice. Both of them are composed of the same thing: hardened lava. However, they clearly have different physical properties. This is caused by the rate at which the lava was cooled. Obsidian formed because the lava was rapidly cooled, creating a crystalline structure. However, pumice forms when lava a long time to cool. The holes in pumice are actually gas bubbles that interferred with the crystallization process. Hope that helps! =D

Answer 3

Examples:  diamond and coal

The way a rock looks depends upon more than only its composition.  Extreme pressure makes the big difference in this example

Answer 4

A lot depends on crystal size, effects of weathering and impurities.