WebMicrocline being an Alkali feldspar tends to have different symmetry and structures at different temperatures which would result in this twinning. Tartan twinning is believed to … WebJun 28, 2015 · o Pericline twinning usually occurs in combination with albite twinning in microcline, but is only observable with the polarizing microscope. The combination of pericline and albite twinning produce a cross-hatched pattern, called tartan twinning, as discussed above, that easily distinguishes microcline from the other feldspars under the ...

Cross-hatched twinning · 1A Collections - University of Cambridge

http://www.alexstrekeisen.it/english/pluto/alkalifeldspar.php WebMicrocline KAlSi3O8 °c 2001 M i neral D t Publi sh g, v o 1.2 Crystal Data: Triclinic. Point Group: 1: Prismatic crystals elongated along [001] or [100], perhaps the largest of any species, to 50m and 13,500t. Cleavable to granular, massive. Commonly exhibits banded perthitic intergrowths from exsolution of albite. Twinning: Carlsbad, moschata squash

Microcline NOVA Mineralogy - nvcc.edu

Webmicrocline, a common feldspar mineral, one form of potassium aluminosilicate (KAlSi3O8) that occurs in igneous rock. Green specimens … Microcline (KAlSi3O8) is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow cooling of orthoclase; it is more stable at lower temperatures than orthoclase. Sanidine is a polymorph of alkali feldspar stable at yet higher temperature. Micr… WebTimes New Roman Arial Wingdings Times Default Design Optical Mineralogy Feldspars Plagioclase Feldspar Alkali Feldspar Ex-Solution Perthites Perthite Photo Zoning Normal or Continuous Zoning Discontinuous Zoning Reverse Zoning Oscillatory Zoning Twinning Carlsbad Twinning Carlsbad Twin Photo Albite Twinning Albite Twin Photo Pericline … mineola ny school calendar