Gemstones are commonly found in pegmatites,which are igneous rocks that are ________.
A)exceptionally mafic
B)extrusive,forming from lava
C)exceptionally coarse grained
D)exceptionally fine grained

Question

Quizplus · Accepted Answer

Pegmatites are igneous rocks with exceptional grain size, and in some rare cases, they can have grains exceeding tens of meters. As pegmatites cool slowly, they can provide the perfect conditions for minerals such as gemstones to form. Therefore, the best answer is C, exceptionally coarse-grained.

Gemstones Are Commonly Found in Pegmatites,which Are Igneous Rocks That