Yes. The faster lava cools, the less time crystals have to form. If the lava cools slowly and has a low viscosity, atoms are able to move around more and form larger crystals.
Most rocks do but there are some exceptions. Coal (such as bituminous coal) is composed of organic material but is considered a sedimentary rock. Glassy rocks such as obsidian or pumice cool too quickly to contain crystals.
The size of the mineral crystals in an igneous rock is related to the rate of time spent in cooling from magma. Longer exposure to the crystallization temperature means larger crystals. Less time means smaller crystals, or in the case of obsidian, which cools extremely quickly, no crystallization.
Partial melting occurs in rocks because the different minerals that compose rocks have different melting points. For example, felsic minerals (e.g. quartz and feldspar) melt at around 700 degrees Celsius while mafic minerals (e.g. pyroxene and olivine) melt at around 1200 degrees Celsius. Therefore, felsic minerals will melt first leaving the mafic minerals solid.Fractional crystallization occurs when minerals from a magma cool and crystallize out of the magma. The first crystals to melt in partial melting will be the first minerals to crystallize out when the magma begins to cool. Therefore, mafic minerals will crystallize first, followed by felsic minerals.Both partial melting and fractional crystallisation tend to produce a more felsic magma than their source rocks.The difference is simply that they are the reverse of one another, heat it up, cool it down. Things that melt first solidify last and separate from one another.
I think what you are trying to say is the sand on a beach cools down easier at more quickly then the ocean water because of convection status, this makes the cool water much more cool then in the ocean water because of radiation.
Magma deep below Earth's surface cools slowly, often at rates of just a few degrees per million years. This slow cooling allows for the formation of larger crystals, as the minerals have more time to grow. As a result, the crystals in rocks formed from deep-seated magma, such as granite, are typically larger than those found in rocks formed from rapidly cooled lava, like basalt.
Extrusive rocks do cool quickly because either the crystals in the rock are very small or there are no crystals at all.
The intrusion is insulated by the surrounding rock, letting it cool very slowly and allowing crystals time to grow to larger sizes. In rapidly cooled rocks the grains can be so small that they are almost undetectable as no significant crystal growth happened.
Extrusive igneous rocks generally have a fine grain texture. This is because they cool quickly on the Earth's surface, causing the minerals to form small crystals.
Intrusive rocks generally have larger crystals because they cool slowly beneath the Earth's surface, allowing for more time for crystal growth. This slower cooling process allows minerals within the rock to form larger crystals compared to extrusive rocks that cool quickly at the surface and have finer-grained texture.
Mostly, it depends on cooling time. If a rock cools very rapidly, a smooth texture is formed as the atoms quickly arrange themselves into a fairly smooth crystalline pattern. Think of obsidian; it cools very fast and has such small crystals looks like black warped glass. However, if a rock was formed below the Earth's surface (intrusively) like in a pluton, it will cool more slowly and will be rougher and have larger crystals.
Large Crystals = Intrusive Small Crystals = Extrusive The name relates to where the minerals were cooled (at at what rate). In the case of intrusive igneous, the rocks were formed above Earth's surface and were thus cooled quickly and the minerals had little time to become defined. Extrusive rocks, therefore, were formed within the Earth's mantle and had a much longer time before being gathered to cool (as they slowly rose to the top).
No. Intrusive igneous rocks have large crystals because they cool slowly.
Extrusive igneous rocks form fine-grained crystals due to rapid cooling at Earth's surface, resulting in minerals like basalt, andesite, and rhyolite. These rocks cool quickly, preventing the formation of large crystals typically found in intrusive igneous rocks.
Igneous rocks can have both small and large crystals, depending on how quickly they cool. If an igneous rock cools slowly beneath the Earth's surface, it can form large crystals, while rapid cooling at the Earth's surface or in an eruption can result in small or no visible crystals.
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Rhyolite is an igneous rock that has formed from rapidly cooling lava or ash.
That's because of the cooling speed. When a magma or a lava cools, it forms crystals. The longer these crystals have the time to form, the larger they will be. However, at the surface, the lava cools relatively fast (at least, compared to magma that stays inside the earth). The crystals in the rock that forms that way don't have a lot of time to form, so don't grow big.