(Solved): Exercise A - A First Pass at Identifying \&' Interpreting Igneous Rocks When determining whether ...

Exercise A - A First Pass at Identifying \&' Interpreting Igneous Rocks When determining whether a sample is coarsely crystalline (phaneritic) or finely crystalline (aphanitic), focus on the majority of the rock. As you will see in Part B, some aphanitic igneous rocks have large crystals (called phenocrysts) scattered in a mass of microscopic crystals. Hence, a few large crystals does not mean a rock is phaneritic. To be considered phaneritic, the majority of a rock should consist of large crystals. Question 1 Based on its color and texture, which type of igneous rock is Sample 1? - Andesite - Basalt - Diorite \( \quad \) - Gabbro - Granite - Rhyolite Sample 1 Question 2 Again, based solely on its color and texture, which type of igneous rock is Sample 2? - Andesite - Basalt - Diorite \( \quad \) Gabbro - Granite \( \quad \) - Rhyolite Sample 2 Sample 2 is 15 cm across. Image courtesy of Sipp Sepp via Sandatlas.com Question 3 Again, based solely on its color and texture, which type of igneous rock is Sample 3? - Andesite - Basalt - Diorite \( \quad \) - Gabbro - Granite \( \quad \) - Rhyolite Sample 3 sample 3 is 8 cm across. Image courtesy of Sipp Sepp via Sandatlas.com Question 4 Which two of samples 1-3 may have the same composition despite their different appearances? (be sure to choose two samples)