microcrystalline texture

geology

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June 30, 2026

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Microcrystalline texture refers to igneous rocks where mineral grains are too small to be seen without magnification. This texture, along with cryptocrystalline, describes aphanitic rocks, which form from relatively rapid magma cooling, typically found in volcanic environments. The size, shape, and arrangement of mineral grains and crystals define a rock's texture, offering insights into its formation and history. In igneous rocks, texture is primarily influenced by cooling rate, but diffusion and crystal growth rates also play a role.12

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igneous rock
Crystallinity
…are further described as either microcrystalline or cryptocrystalline, according to whether or not their individual constituents can be resolved under the microscope. The subaphanitic, or hyaline, rocks are referred to as glassy, or vitric, in terms of granularity.
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…are further described as either microcrystalline or cryptocrystalline, according to whether or not their individual constituents can be resolved under the microscope. The subaphanitic, or hyaline, rocks are referred to as glassy, or vitric, in terms of granularity.
Read More