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Grains in igneous rocks determine the rock's classification. They can be classified as:
- pegmatitic: very large crystals
- phaneritic: rocks contain minerals with crystals visible to the unaided eye, commonly intrusive
- aphanitic: rapid cooling, crystal nucleation and growth is stunted, forming a uniform, fine grained rock
- porphyritic: containing phenocrysts in a fine groundmass
- vesicular: contains voids caused by trapped gas while cooling
- vitreous: glassy or hyaline without crystals
- pyroclastic: rock contain fragments of crystals, phenocrysts and rock fragments
- equigranular: rock crystals are all the same size
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When mineral grains in a metamorphic rock do not form layers the rock has what texture?
no texture
What is a rock's texture?
The texture of a rock consists of it's grain or mineral crystal size, the arrangement of the grains or crystals, and the degree of uniformity of the grains or crystals. Examples of rock texture would be: * Coarse grained--visible crystals or grains as in granite. * Fine grained--small grains, invisible to the unaided eye as in shale. * Porphyritic--large visible crystals in a fine grained matrix as in granite porphyry. * Schistose--layers of flattened micaceous minerals such as in mica schist. * Foliated--a metamorphic rock texture of parallel mineral banding as in gneiss. * Homogenous--same grain apperance in all directions as in basalt.
Which features are extrusive igneous rocks least likely to have?
A)fossils B)small grains C)vesicular texture D) porphyrtic texture Its one of these answers i chose D. because its more likely to have it. Idk if its the right answer.
Can two igneous rocks be made of the same minerals but have different names?
Yes. The grain texture also matters. For example, basalt and gabbro have the same mineral composition, but basalt, which forms on the surface, has microscopic grains while gabbro, which forms underground, has larger mineral grains.
Type of crystal grain that form when molten rock cools quickly?
Small crystal grains form when molten rock cools quickly. In an extrusive igneous rock, it's referred to as aphanitic texture.
A metamorphic rock that has grains arranged in parallel layers has a what texture?
It has a foliated texture.
When mineral grains in a metamorphic rock do not form layers the rock has what texture?
no texture
What is the combination of shapes and sizes of grains?
texture
What is the combination of sizes and shapes of grains?
texture
What is the word that describes the shapes and sizes of the grains in a rock?
They are references to the rock's texture.
When minerals grains flatten and line up in layers a metamorphic rocks has a texture?
A schistose texture.
Soil texture?
The texture of soil depends on its particle size: clay-fine grains, very little space for water. sand- coarse grains, loose, water drains quicklysilt-medium grains, retains water.
What gives rock it's texture?
The sizes,shapes,and positions of the grains that make up a rock.
Which features tells you how large the grains of a sedimentary rock are?
Texture
The word that describes the shapes and sizes of the grains in rock?
Texture.
Rough texture rocks have grains and fine textured rocks have grains?
Yes m that it true, other than glasses all rocks have grains.
The sizes shapes and positions of the grains of a rock determine the rock's?
Texture.
