WebMicrocline from a peraluminous granite. Characteristically featureless in plane light, but the inverse Becke line highlighting technique described above works just as well for microcline. In cross-polarized light you can see the striking “grid” or “tartan plaid” twinning pattern that results from crossing albite and pericline twin domains. WebJan 9, 2014 · Twinning Alteration Association Tactics for Mineral Identification Thin Section Identification Grain Mount Identification Polished Section Identification ... Microcline Adularia Anorthoclase Feldspathoids Nepheline Sodalite Group Leucite Cancrinite-Vishnevite Zeolites Analcime (Analcite)
Leucite - Clark Science Center
WebBoth pericline and albite twinning seem to combine in many plagioclase grains showing a checkerboard (tartan) twinning that gives a false appearance of microcline grid twinning ( … Webmicrocline, a common feldspar mineral, one form of potassium aluminosilicate (KAlSi O) that occurs in volcanic rock.Green specimens are called amazonstone, which is sometimes used as a gem.Microcline forms multiple-twinned crystals and two sets of fine, tapering lamellae at right angles to each other; this tartan twinning distinguishes it from other … dr neal shore
Tartan Twinning in Microcline - YouTube
WebMicrocline is a triclinic K-feldspar and has a characteristic cross-hatched tartan pattern of twinning seen with a petrographic microscope. Orthoclase and sanidine are both optically … WebAug 28, 2024 · Microcline’s tartan plaid, also called cross-hatched, twinning (a combination of albite and pericline twinning) is its most diagnostic characteristic in thin section (Figure 14.26). Plagioclase may show two sets of twins at about 90°, but in plagioclase the twins have sharp parallel boundaries, while in microcline they pinch and swell. WebPlagioclase. Solid solution series between Na-rich end-member (albite) and Ca-rich end-member (anorthite). Triclinic shape contributes to interesting optical angles. (001) is a perfect cleavage, and (010) is also quite good. (110) is a very poor cleavage and is not usually seen in thin section. Cleavages intersect at about 93-94 o angles. dr neal shah