Slow cooling of molten rock leads to rocks with an phaneritic texture; one with larger, visible mineral crystals.
fast cooling rate forms smaller crystals eg Andesiteslow cooling rate forms large crystals eg.Pegmatite
Answer: Crystals usually form from molten rock as the molten rock gradually cools. If the molten rock cools very rapidly, then either small crystals form or no crystals form. An example of this is when lava is ejected from a volcano. If molten rock cools slowly, then large crystals can form. This happens usually when the molten material is very deep in the Earth. Examples of these types of crystals are diamonds, emeralds, rubies, etc.
large rocks
The speed at which the magma/lava cools ie. fast cooling = not much time for crystals to form = little or no small crystals slow cooling = much time for crystals to form = big crystals
Geodes are rocks that are lined or filled with crystals. Pegmatites are rock formations that often exhibit extremely large crystals. Just a note--all rocks are composed of mineral crystals, with few exceptions. The crystals in some, however are just too small to see.
fast cooling rate forms smaller crystals eg Andesiteslow cooling rate forms large crystals eg.Pegmatite
Completely molten rock would not contain any crystals. Most magmas, however, are a mixture of molten and solid crystals of some sort. It is possible that a magma could contain larger crystals of a specific mineral.
large crystals
crystals form from molten rock as the molten rock cools. if the molten rock cools very fast then you may have small crystals growing or no crystals at all. if the molten rockk colls slowly then you then you have large crystals growing. this happens when the molten material is deep in the earth. examples of these types of crystals are Rubies, Emeralds, and Diamonds. crystals may also form when water is evaporated. salt crystals are an example as they form when salt water evaporates.
large
Crystal size in these rock types is determined by their rate of cooling. Pegmatites have large crystals due to very slow cooling. Obsidian has microscopic crystals due to almost instantaneous cooling.
Answer: Crystals usually form from molten rock as the molten rock gradually cools. If the molten rock cools very rapidly, then either small crystals form or no crystals form. An example of this is when lava is ejected from a volcano. If molten rock cools slowly, then large crystals can form. This happens usually when the molten material is very deep in the Earth. Examples of these types of crystals are diamonds, emeralds, rubies, etc.
Any rock created by the cooling of magma or molten material is classified as an igneous rock. These rocks can either be cooled in the earth or on the earths surface. Rocks cooled inside the earth are called intrusive igneous rocks, and have large crystals. Rocks cooled on the earth's surface are called extrusive igneous rocks. These rocks, due to faster cooling times, have very very tiny crystals.
large rocks
They grow large.
Crystals are generally formed when magma or molten rock cools and solidifies. Rapid cooling of the molten rock generally results in the formation of small crystals, like when magma reaches the surface. However, if they cool down slowly, then large crystals are formed. Keeping heat applied allows more growth on the crystal over time. In that logic, larger crystals grow underground.
Slow cooling of igneous rocks typically forms large crystal grains. This is because slow cooling allows more time for mineral grains to grow, resulting in larger crystals. Examples of rocks formed through slow cooling and having large crystal grains include granite and gabbro.