Texture
The glassy texture of obsidian is the best evidence that it formed in an extrusive environment. Obsidian is rapidly cooled lava with no time for crystal growth, resulting in a smooth, glass-like texture.
The Extrusive igneous rock is formed on the earths surface while the Intrusive igneous rock is formed within or inside the earths crust.
Coal is not a intrusive igneous rock but is instead a form of Carbon. The carbon is heated and pressured from low grade metamorphism. Coal is formed mostly from marshes or swamps millions of years ago, think of an environment like the everglades in Florida. A igneous rock would be something like a gabbro or granite.
When magma cools and solidifies, it forms igneous rocks such as granite, basalt, or obsidian. The specific type of rock that forms depends on variables such as the composition of the magma, cooling rate, and environment in which it solidifies.
Igneous rock, specifically extrusive or volcanic rock, is formed when lava cools and hardens. This type of rock typically has small crystals due to the rapid cooling process and examples include basalt and rhyolite.
texture
Texture
texture
The mineral composition and texture of an igneous rock provide the best evidence of the environment in which it was formed. The type of minerals present, their sizes, and how they are arranged can give clues about the temperature and pressure conditions during its formation. Additionally, the presence of specific features like vesicles, crystals, or layering can also indicate the rock's formation environment.
Mineral composition is a key characteristic that provides evidence about the environment in which a rock was formed. Different minerals form under specific temperature, pressure, and chemical conditions, offering valuable clues about the geological processes that shaped the rock.
the date for which the rock formed
The glassy texture of obsidian is the best evidence that it formed in an extrusive environment. Obsidian is rapidly cooled lava with no time for crystal growth, resulting in a smooth, glass-like texture.
Igneous rock is formed when magma cools and becomes solid.
An igneous rock formed from magma is intrusive.
Igneous rock is formed.
Igneous rocks are formed when lava cools. After a eruption, the lava cools, and the igneous rock is formed.
Igneous rock is formed when lava or magma cools.