[DOC] [TLE] Igneous Rocks [PAR] Both magma and lava cool and harden to form igneous rocks. Lava vs. Magma: 
Lava erupting from Kilauea in Hawaii (left); ... When magma cools underground, 
the crust acts like a blanket, insulating it, keeping it warm longer. .... If you see a 
limestone with fossils that resemble corals or any other reef creature, you can... [DOC] [TLE] Igneous Rocks: How Are They Formed? - Universe Today [PAR] Dec 21, 2015 ... Igneous rocks are formed from rising magma, make up the vast ... on the ocean 
floor as a submarine volcano, it becomes lava, by definition. ... Compared to 
intrusive rock, this type of igneous rock cools and ... If the cooling of the lava 
happened more slowly, the rocks would be .... How Do Volcanoes Erupt? [DOC] [TLE] The types of rock: igneous, metarmorphic and sedimentary [PAR] Jan 12, 2015 ... They can form both underground and at the surface. ... That's why you see rocks 
such as granite with big crystals  because the magma had time to cool off. ... 
However, if the magma erupts or is cooled rapidly, then you get what is called a 
volcanic rock  not really igneous, but also originating from lava. [DOC] [TLE] Cooling rate and crystal size [PAR] If the magma cools quickly, the crystals do not have much time to form, ... If the 
magma cools slowly, then the crystals have enough time to grow and become 
large. ... An igneous rock with large crystals probably indicates that the rock 
formed ... was violently erupted onto the surface, where the small crystals were 
formed. [DOC] [TLE] Three Types of Rock - Rock Formed by Cooling and Hardening ... [PAR] Underground, or intrusive, igneous rock forms very slowly. It cools and hardens 
over tens of thousands of years. During this period, the rock's minerals have a... [DOC] [TLE] Igneous Rock Page - Utah Science [PAR] Igneous rocks form from molten rock which is either ejected at the surface of the 
... Pumice cools off very quickly and also is associated with gaseous eruptions. ... 
If granitic lava is light colored, then why is obsidian sometimes black in color? ... 
has rather large crystals because the magma cooled-off very slowly underground
. [DOC] [TLE] Igneous Rocks - Fayetteville-Manlius Schools [PAR] Underground, they are formed when the melted rock, called magma, deep within 
the earth ... As these pockets of magma cool slowly underground, the magma 
becomes igneous rocks. ... Igneous rocks are formed as the lava cools above 
ground. ... If we know this, we can look at a rock and tell if it cooled slowly or 
quickly. [DOC] [TLE] Igneous Rocks - Tulane University [PAR] Sep 3, 2015 ... Volcanic or extrusive igneous rocks form when the magma cools and ... If magma 
makes it to the surface it will erupt and later crystallize to form an extrusive or 
volcanic rock. .... If the raised geothermal gradient becomes higher than the initial 
.... For lava flows cooling times are on the order of days to weeks. [DOC] [TLE] Igneous rocks - BBC [PAR] If the magma cools quickly, small crystals form in the rock. This can ... type of rock. 
They are called extrusive igneous rocks because they form from eruptions of 
magma. ... This can happen if the magma cools deep underground. Granite and... [DOC] [TLE] Igneous Rock Crystallization Animations - ClassZone [PAR] Click the labeled features below to see microscopic views of igneous crystals 
forming ... moving atoms in melted rock become arranged in orderly patterns as 
they cool. ... If melted rock cools instantly, allowing no time at all for the atoms to 
form orderly ... Magma may cool entirely underground, never erupting from a 
volcano. [DOC] [TLE] Rock Key [PAR] Igneous Rock is formed when a magma cools underground and crystallizes or ... 
Magma that erupts onto the surface is called lava. ... If there are a lot of pebbles 
mixed with the sand, it is called gravel. ... All kinds of rocks become sediment. .... 
Crystals: Crystals are what minerals form when they are free to grow in

Question: If it cools underground, it forms igneous rock; if it erupts, it becomes lava
Answer: magma