Plagioclase In Thin Section
Plagioclase Hornblende Quartz And Biotite In A Gneiss From Near Flin Flon Manitoba The Clear Minerals Pp In This Thin Sec Geology Rocks Mineralogy Geology
The Mineralogist Mineralogy Minerals Patterns In Nature
Photomicrograph Tuesday Plagioclase Texture Fabric Textures Metamorphic
Plagioclase Zoned And In A Dacite Porphyry This Plagioclase Has Fine Oscillatory Zoning In Which The Composition Varie Earth Processes Geology Rocks Geology
Tartan Twinning In Alkali Feldspar In A Granite Rocks And Minerals Microscopic Photography Geology
Damage produced during thin section grinding causes speckles of light in.
Plagioclase in thin section. The plagioclase feldspars are named according to the following scheme where the numbers are the percentage of calcium expressed. In thin section plagioclase commonly shows the characteristic albite polysynthetic twinning. In thin section or grain mount the general lack of pleochroism and the twinning are good indicators.
Can be confused with quartz if there is no twinning however the optic axis figure will resolve this. Add tags comment rate. You can find the explanation on the alkali feldspar page.
The composition of a plagioclase feldspar is typically denoted by its overall fraction of anorthite an or albite ab and readily determined by measuring the plagioclase crystal s refractive index in crushed grain mounts or its extinction angle in thin section under a polarizing microscope the extinction angle is an optical characteristic and varies with the. Bytowonite plagioclase im colourless 1 56 1 58 low 40 52 michel levy 80 90 ve low. Also in high grade meta rocks.
The composition of plagioclase feldspar is typically indicated by the general anorthite an or albite ab fraction and is easily determined by measuring the refractive index or peel angle within the crushed particles by measuring the refraction angle under a thin section. In thin section alkali feldspar grains often look like they re sprinkled with dirt ppl or tiny confetti xpl. Small 250x250 max.
This twinning is the most characteristic identifying feature of plagioclase and makes its identification easy when present. Up to cream albite twins along length also carlsbad others in igneous rocks often with clinopyroxene and or olivine. Although some cross hatched twinning may also occur in plagioclase it is always very simple with only one or two cross twins.
Carbonates in thin section unless stained. Pure na alsi 3 o 8 is albite and pure ca al 2 si 2 o 8 is anorthite. Ateration to fine grained material typically occurs along fractures twin planes or cleavages.
Pin On Rocks In Thin Section
Hornblende And Plagioclase Crystals In A Andesite Xpl Image 2x Field Of View 7mm Jeoloji
Olivine And Plagioclase Troctolite Geology Earth Rocks And Minerals
Myrmekite Patch That Appears To Be Replacing Microcline Faint Twins In The Myrmekite Clearly Shows That The Probably Quartz Worms Are Geology Fluid Flow Art
Alkali Feldspar Var Microcline With Tartan Twinning And Perthitic Texture The Light Colored Fuzzy Patches Xpl Light Colors Optical Microscope Feldspar
Antiperthite Unmixing In Plagioclase The Darker Spots In A Charnokite Rogaland Province Norway Xpl Image 10x Fie Geology Mineralogy Beautiful Landscapes
136 Ca Plagioclase Under Microscope Youtube Geology Too Thin Microscopic
Alkali Feldspar Var Microcline In Xpl Showing Distinctive Tartan Twinning Metamorphic Rocks And Minerals Minerals
K Feldspar Jpg 620 380
Photomicrograph Thin Section Of Plagioclase And Pyroxene But If You Look Closely At Its Shape You M Hidden Colors Microscopic Photography Patterns In Nature
Basalt In Thin Section In Xpl With Phenocrysts Of Plagioclase Feldspar And Pyroxene Mostlikely Opx Mineralogy Rocks And Minerals Geology Rocks
Antiperthite Unmixing In Plagioclase Note That The Anthiperthite Have Within Them Perthite Unmixing In A Charnokite Rogaland Pro Mineralogia Minerales Rocas
Plagioclase And Biotite From A Garnet Granulite Artwork Abstract Abstract Artwork
