Quartz
The size of the mineral crystals in an igneous rock is related to the rate of time spent in cooling from magma. Longer exposure to the crystallization temperature means larger crystals. Less time means smaller crystals, or in the case of obsidian, which cools extremely quickly, no crystallization.
The rock would have visible mineral crystals--a phaneritic texture.
Garry Glitter- Rock and Roll
Large amounts of fallen rock are called "talus."But Rock avalanche is a proper term, as is Rock slide, or rockfall.
Temperature doesn't really affect the crystal size; the rate of cooling is the major factor. The faster the mineral, rock, etc. (whatever has the crystals) cools, the smaller the crystals- the slower the larger. If you were "growing" crystals with a set, the warmer the temperature generally means the larger the crystals.
A rock with large crystals indicates that the rock cooled slowly. It is referred to as a phaneritic texture when a rock forms this way.
A rock with large crystals typically has a coarse texture. The large crystals are easily visible and may feel rough to the touch due to their size.
sedimantry
Large crystals are diagnostic of an intrusive igneous rock, as large crystals form as the source magma cools slowly.
A rock with large crystals scattered on a background of much smaller crystals is called a porphyry. This rock texture is the result of two stages of cooling, where large crystals formed during the slower cooling stage, followed by smaller crystals forming during rapid cooling.
granite
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a porphyritic rock. This texture indicates that the rock underwent two stages of cooling: slow cooling deep underground (resulting in the large crystals) followed by faster cooling near the surface (resulting in the small crystals).
Completely molten rock would not contain any crystals. Most magmas, however, are a mixture of molten and solid crystals of some sort. It is possible that a magma could contain larger crystals of a specific mineral.
The large crystals are known as phenocrysts.
The texture is called porphyritic. It forms when an igneous rock cools at different rates, resulting in large crystals (phenocrysts) surrounded by a matrix of smaller crystals (groundmass).
No, melted rock that cools quickly result in igneous rock with large minerals because large crystals take time to form and the rocks that usually have them are the ones that were formed inside the earth.