Yes
Igneous rocks are produced this way but most igneous rocks are produced deep underground by the cooling and hardening of magma. Magma is molten (melted) rock under the surface of the Earth. It is produced in the upper reaches of the mantle or in the lowest areas of the crust usually at a depth of 50 to 200 kilometers.  Obsidian Rock Facts. Obsidian is an igneous rock that forms when molten rock cools very rapidly. The result is a rock that cooled so fast, crystals did not get a chance to form. Obsidian is a volcanic glass with a smooth and uniform structure. Interesting Obsidian Rock Facts: Different varieties of obsidian rock get their names from their appearance. Rondi: Everyone, meet Obsidian. He is an example of an igneous rock because he formed from melted rock, or magma. Obsidian is an extrusive rock, which means he is made from magma that erupted out of a volcano. Igneous rocks that form from magma underground and do not erupt are called intrusive..  Igneous rocks are also formed when volcanoes erupt. Igneous rocks are formed as the lava cools above ground. The upper 16 km of the Earth’s crust is composed of 95% igneous rock. Intrusive igneous rocks are formed from magma that cools and solidifies underground. These rocks are coarse grained. The answer to how are igneous rocks formed is pretty straight forward: Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when magma deep within the Earth becomes trapped in small pockets. As these pockets of magma cool slowly they become igneous rocks. Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  ♦ Lava is molten rock that flows out of a volcano during an eruption. ♦ Lava is the term used to describe igneous rocks formed during a lava flow. ♦ Intrusive rocks form near the Earth’s surface while plutonic rocks cool deep underground. 2. is the term used to describe igneous. rocks formed in a lava flow. 4. Intrusive rocks form near the Earth’s surface while. rocks cool deep underground. 6. Tephra are igneous rocks blown into the. during a volcanic eruption. 8. Lava is the rock that flows out of. The best obsidian is formed underground near a volcanic vent because those rocks will have limited impurities. Obsidian flows are so slow that often other obsidian flows will occur on top of each other causing a streaked appearance in the obsidian rock. The result is a rock that cooled so fast, crystals did not get a chance to form. Obsidian is a volcanic glass with a smooth and uniform structure. Interesting Obsidian Rock Facts: Different varieties of obsidian rock get their names from their appearance. Igneous rocks are classed on the basis of where they form and the compostion of the molten rock. Igneous rocks form from molten rock which is either ejected at the surface of the earth or cools off underground. When volcanoes erupt, they can eject molten rock as shown in the following picture. This hot, thick lava flows down the side of the volcano and eventually cools Igneous Rocks are formed when magma (hot, molten material from deep within the earth) cools. When it cools at the surface after pouring out of a volcano, it typically forms lava. When magma explodes out of a volcano, it can form fragmented (pyroclastic) rock, ash-flow tuffs, and volcanic glass (obsidian). When magma cools slowly deep underground, it forms granite.
http://volcano.oregonstate.edu/igneous-rocks-lesson-12 http://www.softschools.com/facts/rocks/obsidian_rock_facts/372/ http://www.amnh.org/ology/features/ifrockscouldtalk/obsidian.php http://www.universetoday.com/82009/how-are-igneous-rocks-formed/ https://en.wikipedia.org/wiki/Igneous_rock http://www.ringoffirescience.com/support-files/l1-igneous-rocks-sample-lesson.pdf http://www.softschools.com/facts/rocks/obsidian_rock_facts/372/ http://utahscience.oremjr.alpine.k12.ut.us/sciber99/8th/earth/sciber/rocks2.htm http://www.birdandhike.com/Rocks/Igne/_Igne_index.htm
is obsidian formed underground