Extruded lava.
Glassy rocks are rocks that have cooled and solidified quickly, without forming crystals. This rapid cooling prevents mineral crystals from growing, resulting in a smooth and glass-like texture. Obsidian and pumice are examples of glassy rocks.
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.
obsidian
They cool to quickly for crystals to form.
A glassy texture.
Obsidian is a type of glassy lava not a gas.
The texture of a rock depends on the rate that it cools. Obsidian cools so quickly that no crystals can form, therefore giving it a glassy texture.
Obsidian.
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.
Smooth glassy lava is called obsidian. It forms when lava cools quickly, preventing crystals from forming, resulting in a glassy texture. Obsidian is typically black in color but can also appear in various shades of brown, green, or red.
obsidian
Obsidian