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Describe the texture of obsidian?
Obsidian is a hard, dark volcanic rock that is formed by the rapid solidification of lava. Its texture is glassy and shiny black.
What is the glassy surface on a clay vessel called?
It is called a glaze.
What is the difference between texture and composition?
BASCILY texture is feel of something an Composition is what does it take to make up something.Texture is based on the sizes, shapes and position of the rocks grains. The Composition of a rock is determined by the minerals that make up the rock. Composition and texture are two characteristics that scientists use to classify rocks.
What is Lava that flows slowly to form a glassy surface with rounded wrinkles called?
The lava is pahoehoe Lava.
What are igneous extrusions?
== == Extrusive igneous rocks are formed from the solidification of lava on or above the surface. Rapid cooling from exposure to air or water results in rapid crystallization of their component minerals, normally creating a fine grained texture as opposed to intrusive igneous rocks which have a coarser texture. Examples of extrusive igneous rocks would include obsidian, pumice, basalt, and rhyolite.
What is the texture of the very finest grained rocks called?
vitreous or glassy (obsidian)
Lava that cools so quickly that ions do not have time to arrange into crystals will form igneous rocks with a?
fine-grained, glassy texture.
What igneous rocks does not have a glassy texture?
Granite, diorite, and gabbro are examples of igneous rocks that do not have a glassy texture. These rocks are formed from slowly cooled magma underground, allowing time for crystals to grow, giving them a coarse-grained appearance.
Is chert glassy?
Chert is a cryptocrystalline siliceous sedimentary rock. It resembles the physical properties of rocks having a glassy texture and a conchoidal fracture.
What is the difference between a glassy texture and that of other volcanic rocks?
Glassy texture forms when lava cools rapidly, trapping gases and preventing crystal formation. Other volcanic rocks have crystalline textures due to slower cooling rates that allow minerals to form. Glassy rocks like obsidian lack mineral grains, while other volcanic rocks like basalt or granite have visible minerals in their composition.
What does term ''glassy'' mean when talking about igneous rock texture?
Glassy texture in igneous rocks refers to a smooth and reflective appearance resembling glass. This texture is formed when the molten rock cools rapidly, preventing mineral crystals from developing. Glassy texture is typically seen in obsidian, a type of volcanic glass.
What is the texure of obsidian?
Obsidian is an igneous rock with a glassy texture. Its texture is also called hyaline, the Greek word for texture.
What texture does obsidian have?
A glassy texture.
What texture of obsidian?
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.
Why is a igneous rock appear smooth and glassy?
Some igneous rocks are very smooth and glassy (obsidian) while others have a very rough texture, such as the rocks used on the bottom of a propane gas grill. They are all formed from lava, but the glassy rocks cooled so fast that crystals did not have a chance to form. The rougher rocks cooled more slowly, allowing larger crystals to form--Slower cooling = larger crystals = rougher texture.
Do Glassy igneous rocks form when magma cools so slowly that mineral crystals cannot grow?
No, glassy igneous rocks form when magma cools so quickly that mineral crystals do not have time to form. This rapid cooling prevents the atoms in the magma from arranging themselves into a crystalline structure, resulting in an amorphous, glassy texture.
What are the different types of rock texture?
The main types of rock texture are crystalline, fragmental, glassy, and vesicular. Crystalline rocks have interlocking mineral grains, fragmental rocks are made up of broken fragments of pre-existing rocks, glassy rocks have no crystal structure due to rapid cooling, and vesicular rocks have cavities or bubbles caused by gas escaping during solidification.
