Larger crystal size is generally associated with longer cooling times, because large crystals take a long time to form. For this reason, intrusive (underground) igneous rocks have larger crystals than extrucive (above ground) rocks, due to the lack of insulation, and hence faster cooling, at the surface.
Some rocks may contain crystals, but not all rocks contain crystals. Crystals can be found in rocks that have volcanic origin.
Some rocks have crystals because the minerals within them cooled and solidified slowly, allowing enough time for the atoms to arrange themselves in an ordered, repeating pattern. This orderly arrangement forms crystals with distinct shapes and structures, giving the rock its crystalline appearance.
Aphanitic igneous rocks have individual mineral crystals that are too small to be seen without magnification. These rocks cool rapidly, resulting in the formation of tiny crystals. Examples include basalt and rhyolite.
Igneous rocks such as granite and basalt often contain crystals, as they form from the cooling of molten magma. Metamorphic rocks like marble and quartzite can also have crystals, which form due to the recrystallization of minerals under high pressure and temperature conditions. Some sedimentary rocks like limestone may have crystals that grew in gaps or voids within the rock.
Plutonic rocks are intrusive (they solidify before they reach the surface) and have larger crystals because the crystals have had a longer time to accumulate in the heat under the surface. Volcanic rocks are extrusive (they solidify on or near the surface) and have smaller crystals because the element has less time to accumulate when they cool quickly.
some of them are formed inside the earth and take 100's of years to form and form large cyclists in that time
All rocks have crystals, or at least crystalline structures. Sedimentary rocks may not have crystals as such, but the individual grains have internal crystal structures. All magmatic and metamorphic rocks have crystals, though they may be too small to be seen without the aid of a microscope. Only possible exception is Obsidian (volcanic glass) which may be amorphous.
Some rocks may contain crystals, but not all rocks contain crystals. Crystals can be found in rocks that have volcanic origin.
It varies some metamorphic rocks are fine grained (eg slate) and others have very large crystals (eg an augen gneiss).
Some rocks have crystals because the minerals within them cooled and solidified slowly, allowing enough time for the atoms to arrange themselves in an ordered, repeating pattern. This orderly arrangement forms crystals with distinct shapes and structures, giving the rock its crystalline appearance.
Igneous rocks with big crystals or grains form from slow cooling beneath the Earth's surface, allowing time for larger crystals to grow. In contrast, igneous rocks with small crystals or grains form from fast cooling at or near the Earth's surface, limiting the time available for crystal growth.
The reason why is because of where it comes from in a volcano and how fast it cools. If it cools slowly then it will have bigger crystals because the longer it has to cool the longer the crystals have to grow. So dose that answer your question
The earth is composed of various types of rocks, some formed as a result of pressure while others due to cooling. Igneous rocks form when molten lava cools and solidify to form crystals.
yes there are some rocks that are round called geodes these rocks are hollow on the inside and have crystals inside them
Aphanitic igneous rocks have individual mineral crystals that are too small to be seen without magnification. These rocks cool rapidly, resulting in the formation of tiny crystals. Examples include basalt and rhyolite.
The size of the crystals depend on the time it took the rock to cool. Slow cooling rocks have larger crystals because they had a longer time to grow their crystals. For example Basalt is an volcanic extrusive igneous rock that forms from rapid cooling of the magma and are usually located near the surface or on the ocean floor, it has finer crystals not visible by the naked eye. Granite is an intrusive igneous rock that forms from slow cooling of the magma within the earth crust, it has larger crystals.
Some are, not others.