What would you name an intermediate coloured (35% dark minerals), phaneritic rock with large greenish-black amphibole phenocrysts?
A)hornblende diorite porphyry
B)porphyritic hornblende granite
C)hornblende andesite breccia
D)porphyritic hornblende gabbro

Question

Quizplus · Accepted Answer

The intermediate colour suggests that the rock is not predominantly light or dark in colour, placing it within the realm of diorites. The large greenish-black amphibole phenocrysts point towards hornblende being the dominant mineral, and the phaneritic texture suggests slow cooling. The use of the term 'porphyry' also implies a porphyritic texture like this rock. Thus, the best choice for the name of this rock would be 'hornblende diorite porphyry'

What Would You Name an Intermediate Coloured (35% Dark Minerals)