What is the difference in the appearance of igneous, sedimentary and metamorphic rocks?

Igneous rocks are distinguished by a dense structure, porosity and the presence of crystals of various sizes in the structure. They also differ in strength.
Sedimentary rocks mostly have a porous structure. This is due to the influence of water and other natural phenomena. They are inferior in strength to the other two groups.
Metamorphic rocks are distinguished by a granular structure. This can be clearly seen in the example of marble, if you look at a piece of it under light. They are also distinguished by layering.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.