Which phrases describe non-foliated rocks? Check all that apply.
A. have grains in parallel layers
B. have randomly arranged grains
C. include quartzite and marble
D. tend to split along their bands
E. form from crystallized magma
The correct answer and explanation is:
The correct answers are:
✅ B. have randomly arranged grains
✅ C. include quartzite and marble
Explanation:
Non-foliated rocks are a type of metamorphic rock that do not have a layered or banded appearance. Unlike foliated metamorphic rocks, which have minerals aligned in layers due to high pressure, non-foliated rocks have randomly arranged grains and lack visible banding.
Why the correct choices are B and C?
- (B) Have randomly arranged grains:
Non-foliated rocks form under conditions where pressure is either low or applied equally in all directions. As a result, the minerals do not align into layers but instead remain in a random arrangement. This is a key characteristic of non-foliated rocks. - (C) Include quartzite and marble:
Quartzite and marble are common examples of non-foliated metamorphic rocks.- Quartzite forms when sandstone is subjected to heat and pressure, recrystallizing its quartz grains without forming layers.
- Marble originates from limestone or dolomite and undergoes metamorphism, resulting in a smooth, crystalline texture.
Why the other choices are incorrect?
- (A) Have grains in parallel layers ❌
This describes foliated metamorphic rocks like schist and slate, where minerals are aligned in distinct bands due to directed pressure. - (D) Tend to split along their bands ❌
Foliated rocks tend to split along their bands, but non-foliated rocks do not have bands and instead break irregularly. - (E) Form from crystallized magma ❌
Metamorphic rocks do not form from magma. Rocks that crystallize from magma are igneous rocks, such as granite and basalt.
Now, I’ll generate an image of non-foliated metamorphic rocks like quartzite and marble, showing their randomly arranged grains and crystalline texture.
Here is the generated image of non-foliated metamorphic rocks (quartzite and marble), showcasing their smooth, crystalline textures and randomly arranged grains without visible layering or banding. Let me know if you need any modifications or additional details!
