Not necessarily. Intrusive igneous rocks, especially pegmatites, can have large crystals.
Both plutons and pegmatites are formed from the slow cooling of molten rock beneath the Earth's surface. This slow cooling allows for the formation of large mineral crystals. Additionally, both plutons and pegmatites can contain a variety of minerals, often including rare or uncommon ones due to the unique conditions of their formation.
Sapphires are mined from http://www.answers.com/topic/alluvium deposits or from primary underground workings. They form in rocks called pegmatites
When magma coos slowly, it allows large crystals to form. The process of evaporation helps to form crystals.
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.
slow cooling of gaseous magma
Veins of extremely coarse-grained igneous rocks are called pegmatites. These veins form from the crystallization of mineral-rich magma, resulting in very large crystals due to slow cooling and high water content. Pegmatites are commonly found in association with granitic rocks.
Not necessarily. Intrusive igneous rocks, especially pegmatites, can have large crystals.
i think the answer is pegmatites or something... i just googled it myself your corect it is pegmatites
Veins of extremely coarse-grained igneous rocks are referred to as pegmatites. These veins are formed from the last minerals to crystallize in a cooling magma, resulting in very large crystals. Pegmatites can contain economically valuable minerals such as lithium, beryllium, and rare earth elements.
pegmatites
Both plutons and pegmatites are formed from the slow cooling of molten rock beneath the Earth's surface. This slow cooling allows for the formation of large mineral crystals. Additionally, both plutons and pegmatites can contain a variety of minerals, often including rare or uncommon ones due to the unique conditions of their formation.
They are associated with the late stages of granite intrusions and the minerals formed in pegmatites literally had the time to enjoy the benefits of a slow crystallization process from a rich chemical stew produced by the cooling granite. For an alternate hypothesis, see the link below.
Yes. Salts can form crystals (salt crystals).
Mineral specimens with very large crystals most likely formed in environments with slow cooling rates and sufficient space for crystal growth, such as pegmatites or hydrothermal veins. These conditions allow for the growth of larger crystals due to reduced competition for space and slower precipitation rates.
A pegmatite is a rock formed under certain favorable circumstances that enhance the crystal size of the rock. The crystals would be larger than those in basalt, an extrusive igneous rock, and granite, and intrusive igneous rock.
Sapphires are mined from http://www.answers.com/topic/alluvium deposits or from primary underground workings. They form in rocks called pegmatites