What does Holocrystalline mean?
Definition of holocrystalline : completely crystalline : made up wholly of crystals or crystalline particles —used of a rock (as granite)
What is Allotriomorphic?
Definition of allotriomorphic : marked by a form different from the normal or expected because of development in special circumstances —used especially of mineral grains of igneous rocks whose mutual growths have prevented the assumption of outward crystal form —contrasted with idiomorphic.
What is Hypidiomorphic?
Definition of hypidiomorphic : partly idiomorphic —used of a rock only some of whose constituents have a distinct crystalline form.
How is Holocrystalline formed?
If the cooling period is long enough to let the atoms form orderly patterns and mineral crystals fully grow, the rock then has minerals with large particle size and crystal shape, which can be seen by eyes or low-magnification microscope. In this case, the rock is known as “holocrystalline”.
What is Panidiomorphic texture?
Panidiomorphic refers to a texture in which, theoretically all the component mineral grains are subhedral. Allotriomorphic refers to a texture in which all the component mineral grains are anhedral.
What does a porphyritic rock look like?
Porphyritic – This texture describes a rock that has well-formed crystals visible to the naked eye, called phenocrysts, set in a very fine grained or glassy matrix, called the groundmass.
What is Holocrystalline texture?
Said of the texture of an igneous rock composed entirely of crystals, i.e., having no glassy part. Also, said of a rock with such a texture.
What is Poikilitic in geology?
Poikilitic texture describes the occurrence of one mineral that is irregularly scattered as diversely oriented crystals within much larger host crystals of another mineral.
What is euhedral in geology?
Euhedral crystals (also known as idiomorphic or automorphic crystals) are those that are well-formed, with sharp, easily recognised faces.
What is the definition of porphyritic?
Definition of porphyritic 1 : of or relating to porphyry. 2 : having distinct crystals (as of feldspar) in a relatively fine-grained base.
What igneous rocks are porphyritic?
Explanation: A porphyritic texture is one that is characterised by large crystals (phenocrysts) in a finer groundmass (aphanitic part). So, many rocks are porphyritic: andesite, granite and even some basalts.