Cool rapidly
Obsidian has a glassy texture because it cools very quickly when erupted onto the Earth's surface. This rapid cooling prevents crystal formation, resulting in a smooth, glass-like appearance. The high silica content of obsidian also contributes to its glassy nature.
Obsidian is an extrusive igneous rock that forms when lava cools quickly and solidifies into a glass-like material without crystal formation. It is typically black in color and has a smooth, glassy texture due to its rapid cooling process.
Obsidian is an extrusive igneous rock with a mafic composition and a glassy texture. This rock forms from the rapid cooling of lava with high silica content, preventing the growth of mineral crystals and resulting in its glassy appearance.
cool too quickly for mineral grains to form, resulting in a non-crystalline structure.
obsidian
They cool to quickly for crystals to form.
Andesite is considered an extrusive igneous rock.
Obsidian is an glassy, extrusive, igneous rock that is found in areas that have experienced rhyolitic eruptions. Obsidian is formed when the rhyolitic lava comes into contact with water. This quick-cooling results in the glassy texture of obsidian.
Obsidian has a glassy texture because it cools very quickly when erupted onto the Earth's surface. This rapid cooling prevents crystal formation, resulting in a smooth, glass-like appearance. The high silica content of obsidian also contributes to its glassy nature.
Obsidian is an extrusive igneous rock that forms when lava cools quickly and solidifies into a glass-like material without crystal formation. It is typically black in color and has a smooth, glassy texture due to its rapid cooling process.
Obsidian.
Obsidian is an extrusive igneous rock with a mafic composition and a glassy texture. This rock forms from the rapid cooling of lava with high silica content, preventing the growth of mineral crystals and resulting in its glassy appearance.
cool too quickly for mineral grains to form, resulting in a non-crystalline structure.
obsidian
cool rapidly
Obsidian is an igneous rock. However it differs from other rocks because it contains no minerals. It consists of natural glass, which is not a mineral because it has no crystal structure.Answers from McDougal Littell, Earth Science book
Obsidian is an extrusive rock that cooled very rapidly without forming crystals. As a result, obsidian has a smooth, shiny texture of a thick piece of glass.