If a magma that is rich in Silicon and Aluminum cools over thousands of years underground, it forms Granite. If it cools quickly when it erupts from a volcano, it forms Rhyolite.If a magma that is rich in Iron and Magnesium cools over thousands of years underground, it forms Gabbro (which is sold as "black granite" at home improvement stores). If it erupts from a volcano, it also forms a black rock, but because it cools quickly, the crystals can only be seen under the microscope/ This rock is  _________Although _________ not common on continents, this rock is the most common rock on Earth's surface, because it forms the ocean floor. It is also the rock that makes up the Hawaiian islands, famous for their beautiful volcanoes and river-like lava flows.Group of answer choicesobsidiangranitebasaltpumice

Generally, a rock that is black is made up of crystals that are rich in Iron and Magnesium. This is NOT the case with this rock (____________), which is instead rich in Silicon and Aluminum.  Its pitch-black, shiny appearance is due to the ABSENCE of crystals - it is pure GLASS. It forms from magma that is so gooey that elements cannot "move around" through it to arrange themselves into crystals.Group of answer choicesobsidiangranitebasaltpumice

The minerals that form when magma crystallizes slowly deep underground areGroup of answer choicesvisible without a microscopeglassyvisible with a microscope only

Extrusive rocksGroup of answer choicesare generally made up of large mineralsare made up of precipitatesare also called volcanicform deep under volcanoes

Sedimentary rocks hold clues toGroup of answer choiceshow minerals crystallize from magmapressure and temperature in Earth’s deep interiorprocesses that cause volcanoes to eruptenvironments that existed on Earth’s surface in the past

Magma that is ejected during a volcanic eruption forms _____ igneous rocks.