What are the influencing factors for large crystal formation? And what types of rocks have enlarged crystals?

Question

3. What processes transform igneous rock to sediment?
4. What processes transform sediment to sedimentary rocks?
5. What process transforms metamorphic rock to magma?

Answer 1

Large crystals form when there is space for them and when there is sufficient chemicals of the proper type for them to continue to grow. Pegmatites are a type of felsic igneous rock in which large, and often rare minerals grow.

Weathering, both chemical and physical, will turn any rock into sediments.

Pressure (compaction) and/or cementation from mineral-laden fluid flow will form sedimentary rocks. Compaction is more important for fine grained sediments like mud, while cementation is more important for larger grains like sand, although both play a part in lithophication of both sediments.

Extreme heat, decreased pressures, and or mixing with fluids can turn any rock type into magma.

The question that seems to belong here but isn't listed is "How are metamorphic rocks formed?", so I'll answer that one in case you forgot. :) Metamorphic rocks are formed when any rock type (even other, older metamorphic rocks!) are exposed to high pressures and temperatures. The amount of pressure and temperature (plus the composition of the original rock) will determine what kind of metamorphic rock is made.

Answer 2

The major influencing factors are time and amount of that mineral (or the elements that make the mineral such as silicon and oxygen for SiO2). The longer the time elapsed in the cooling of molten rock, the larger the crystals can grow. Quartz crystals have been found in immense sizes, coffee table, room, house size and more. Of course, if a mineral that crystalizes at a higher temperature has reduced the space avaliable, the crystals will not be as big.

A good example of a rock with larger crystals of minerals is porphry. Another is some types of granite that have been far enough underground to cool very slowly. Many of the samples you see in granite will have large areas of one mineral.

Processes that transform igneous rock to sediment are various types of erosion. This would include water, wind, scaling (rock breaking off due to water freezing in cracks, etc) As the debris of the igneous rocks are worn down into dust, sand, and silt, they are deposited into layers, areas, water, and so on to form sediment.

Processes transforming sediment to sedimentary rock are mainly the pressure of the land/sediment above them, as layer after layer is built up compacting the sediment. there is allso cementation, where you wil see debris of differing sizes together in a sedimentary rock.

Metamorphic rocks are transformed into magma by heat and pressure. Pressure will raise the temperature of the rock, and the immense prossure will raise it to the melting point of the minerals. Also, rock forced into liquid rock will melt if the temp is high enough for the individual minerals. Some parts will then melt slower than others.

Answer 3

the influencing factors for large crystal formation-
-Time
-Temperature
-pH
-Pressure
-Velocity
-Particle Size
-Other Environmental Factors
types of rocks have enlarged crystals are-

you will find a lot of your larger crystals in different rocks...
when lava takes longer to cool crystals have more time to crystalize and grow. usually when envirenmental factors have the right conditions like the list I gave you above then crystals have the chance to Grow. http://www.caosclub.org/totalcaos/members/caosho24.html This site is pretty cool incase you want to make a crystal to sort of see how they form.

and to answer your 3 Qs. What you are asking is the rock cycle

Magma cools and crystallizes to form igneous rock.

Igneous rock undergoes weathering (or breakdown) to form sediment. The sediment is transported and deposited somewhere (such as at the beach or in a delta, or in the deep sea).

The deposited sediment undergoes lithification (the processes that turn it into a rock). These include cementation and compaction.

As the sedimentary rock is buried under more and more sediment, the heat and pressure of burial cause metamorphism to occur. This transforms the sedimentary rock into a metamorphic rock.

As the metamorphic rock is buried more deeply (or as it is squeezed by plate tectonic pressures), temperatures and pressures continue to rise. If the temperature becomes hot enough, the metamorphic rock undergoes melting. The molten rock is called magma. This completes the cycle.

Answer 4

The longer rock takes to cool the larger the crystals grow.

A large crystal in granite is called a phenocryst. This type of granite could be described as phenocrystaline granite. These crystals may be composed of feldspa, or tormoline, little rusty sorry.

Gabbro, Peridotite: some other rocks with potential for large crystals.