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Twinning is crystallographically defined by its twin plane 𝑲 𝟏, the mirror plane in the twin and parent material, and 𝜼 𝟏, which is the twinning shear direction. Deformation twins in Zr are generally lenticular in shape, lengthening in the 𝜼 𝟏 direction and thickening along the 𝑲 𝟏 plane normal.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Pericline also refers to a doubly plunging anticline or syncline.. Pericline is a form of albite exhibiting elongate prismatic crystals. [1]Pericline twinning is a type of crystal twinning which show fine parallel twin laminae typically found in the alkali feldspars microcline. [2]
Microcline may be clear, white, pale-yellow, brick-red, or green; it is generally characterized by cross-hatch twinning that forms as a result of the transformation of monoclinic orthoclase into triclinic microcline. The chemical compound name is potassium aluminium silicate, and it is known as E number reference E555.
Plagioclase in hand samples is often identified by its polysynthetic crystal twinning or "record-groove" effect. Plagioclase is a major constituent mineral in Earth's crust and is consequently an important diagnostic tool in petrology for identifying the composition, origin and evolution of igneous rocks.
Orthoclase crystal twinning from the Organ Mountains in New Mexico. Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite. Typically, the pure potassium endmember of orthoclase forms a solid solution with albite, the sodium endmember (NaAlSi 3 O 8) of plagioclase.
Twinning (making a twin of) may refer to: In biology and agriculture, producing two offspring (i.e., twins) at a time, or having a tendency to do so; In engineering and manufacturing, the creation of a digital twin or the synching of such twins; Twinning (cooperation) Afri Twin, an exchange partnership between schools in the United Kingdom and ...
In geology and materials science, a deformation mechanism is a process occurring at a microscopic scale that is responsible for deformation: changes in a material's internal structure, shape and volume. [1] [2] The process involves planar discontinuity and/or displacement of atoms from their original position within a crystal lattice structure.