Question

Why are metamorphic rocks considered as good building material

Answer 1

It should be noted that not all metamorphic rocks make good construction materials. The previously mentioned rocks contain large amount of quartz, making then hard and resistant to chemical weathering. Orthogneisses, gneiss from an igneous rock, can often times be just as strong as any granite or diorite. But, many metamorphic rocks, after enjoying deformation and metamorphism, are left with many fractures and veins, which leave then weaker. Mylonites can be this way. Schists and phyllites usually have a higher mica content (biotite, muscovite, and chlorite). These minerals are platy and soft. Schists themselves are very platy and don't make great dimension stone or aggregate.

Answer 2

Explanation:

The previously mentioned rocks contain large amount of quartz, making then hard and resistant to chemical weathering.But, many metamorphic rocks, after enjoying deformation and metamorphism, are left with many fractures and veins, which leave then weaker. Mylonites can be this way.