All rock does not contain mineral crystals. Obsidian, or volcanic glass, in particular is a rock that has cooled so quickly from lava that mineral crystals were not able to form.
Some igneous rocks are very smooth and glassy (obsidian) while others have a very rough texture, such as the rocks used on the bottom of a propane gas grill. They are all formed from lava, but the glassy rocks cooled so fast that crystals did not have a chance to form. The rougher rocks cooled more slowly, allowing larger crystals to form--Slower cooling = larger crystals = rougher texture.
Extrusive rocks do cool quickly because either the crystals in the rock are very small or there are no crystals at all.
All rocks can form from sedimentary because the rock cycle is endless.
They form by sediments of rocks getting squeezed together at the bottom of a lake. Some of those rocks are Conglomerate, Limestone, and Sandstone.
All Igneous rocks are crystalline, but also note that Metamorphic rocks are also often crystalline, at least to a certain extent. Both of these categories always contain some crystals.
Some rocks may contain crystals, but not all rocks contain crystals. Crystals can be found in rocks that have volcanic origin.
Crystals can form in all three types of rocks. Igneous rocks, like granite, form from the cooling and solidification of magma. Sedimentary rocks, such as limestone, can contain crystals that formed from precipitation of minerals in water. Metamorphic rocks, like marble, can have crystals that grew under extreme heat and pressure.
Yes. All intrusive igneours rocks and many extrusive rocks have crystals.
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.
If a rock has large crystals, it is an intrusive rock. Intrusive rocks form underneath the Earth's surface. Magma cools slowly so it has time to form large crystals. An example is granite, where you can see the crystals with your naked eye. Rocks that have small crystals are extrusive rocks. Extrusive rocks are ones that form from lava (blasted out of a volcano) so they cool very quickly, not allowing large crystals to form. An example is obsidian, where you cannot visibly see the small crystals; it just looks like one black, glassy rock.
No, not all extrusive igneous rocks contain visible crystals. Some extrusive rocks, such as obsidian and pumice, cool so quickly that mineral crystals do not have a chance to form, resulting in a glassy texture instead.
Not all of them. Volcanic glass does not have crystals.
Pretty much all of them with the exception of things like obsidian, which is a glass and by definition not crystalline. Note that the crystals in question may be extremely small (microcrystalline).
It depends on the cooling rate of the magma. If the magma cools slowly underground, large crystals can form, creating intrusive igneous rocks. If the magma cools rapidly on the Earth's surface, small crystals or glassy textures can result in extrusive igneous rocks.
No, crystals and rocks are not the same. Rocks are made up of one or more minerals, while crystals are solid substances in which the atoms are arranged in a highly ordered structure. Crystals can be found in rocks, but not all rocks contain crystals.
No that doesnt matter all rocks are rocks !
All salts can form crystals.