Answer :
Final answer:
The two main types of metamorphic rock textures are foliated, which is banded or layered due to aligned minerals, and non-foliated, which appears massive with no visible mineral alignment. Slate and gneiss are examples of foliated rocks, while marble and quartzite exemplify non-foliated rocks.
Explanation:
The two primary types of metamorphic rock textures are foliated and non-foliated. Foliated metamorphic rocks exhibit a banded or layered appearance due to the alignment of mineral crystals within the rock.
This alignment might be parallel or show overlapping sheets of platy minerals like micas or layers of light and dark minerals.
Examples of foliated rocks with varying grain sizes include slate, gneiss, and phyllite. Sometimes, foliated rocks can also display textures due to high-pressure conditions such as mylonitic textures.
On the other hand, non-foliated metamorphic rocks do not show any mineral alignment and tend to appear massive and structureless. These rocks might break across mineral grains, leading to a scaly surface.
Common non-foliated rocks include marble and quartzite, which originate from the metamorphism of limestone and sandstone, respectively.
Identification of these rocks includes an analysis of the rock's composition, the textures mentioned above, probable parent rocks or protoliths, and the conditions of metamorphism that they have been subjected to. This comprehensive understanding informs geological analysis and classification.
