igneous
The texture thus described is referred to as aphanitic texture.
You can describe the rock by the process that allowed it to cool quickly: "Extrusive" or you can describe it by its texture: "aphanitic". An extrusive rock tends to be aphanitic = Rocks formed from lava flows tend to have small crystals.
When lava cools quickly, the minerals in it form very tiny crystals which can usually only be seen under a microscope. To the eye, this results in a smooth appearance.
noo, very very slowly :)
No. Pumice cools very rapidly above the surface. It is a glassy rock. Glass forms when lava cools too quickly for crystals to form.
Pumice is an igneous rock. Pumice is formed by hot lava filled with gas cools quickly and forms.
composite volcano
because the crystal in the rock is very small
Very can be an adjective, or an adverb.It is an adverb in "She did it very quickly" It is an adjective in "At the very back of the shop"
Igneous rock that cools very quickly forms a fine-grained or avelor texture, as the rapid cooling does not allow large crystals to develop. This results in a rock that may appear glassy or contain very small mineral grains that are difficult to see without a microscope. An example of this type of rock is basalt, which often forms from lava that cools quickly upon contact with air or water.
Obsidian is an igneous rock that forms from lava cooling extremely quickly, preventing the formation of crystals. It is often referred to as a natural glass due to its lack of crystal structure.
Extrusive rocks do cool quickly because either the crystals in the rock are very small or there are no crystals at all.