Petrography of the quartz sandstone from the Chełmo Mount. (a) Fine-to medium-grained, well sorted quartz sandstone, cemented by siliceous cement, polarized light microscopy image, crossed nicols; (b) SEM-BSE (Scanning Electron Microscope-BackScattered Electron) image of the same sample area; Ilm-ilmenite; Qtz-quartz.
Outcrops of Albian clastic rocks in the Miechów Segment. (a) The wall of loose yellow and white sands in a sandpit at Glanów-Stroniczki, (b) Abandoned quarry of lithified yellow quartz sandstone on top of the Chełmo Mount.
Polycrystalline Quartz - plain polarised light - Granite petrofabric, Belize
Microscopic petrology and pore characteristics of silicified segment of Shunnan 4 well in Tazhong area. (a) Euhedral quartz grains are common in the fine-grained limestone. Strong recrystallization led to the formation of fine-grained calcite (plane polarized); (b) and (c) strong silicification and pervasive intergranular spaces between subhedral-euhedral quartz grains (plane polarized); (d) plenty of intergranular pores are partly filled with bitumen (plane polarized). Qtz, Cal, and Bitu indicate quartz, calcite, and bitumen, respectively.
Schist with Quartz. Thin section in plane polarized light. 32X
Microstructures of quartz of the quartz and quartz feldspar veins from the Guider syenitic pluton. (a) Quartz 1 cracked and recrystallized into rims. Cracks are filled with quartz 2 and sericite; (b) Large recrystallized quartz 1 crystals and intracrystalline deformation structures irregular (zoned) and regular (sweeping) undulose extinctions; (c) Quartz 2 recrystallized in chevron folds with an axial plane parallel to foliation, around quartz 1; (d) Quartz 2 and opaque minerals (oxides and sulphides) stretched according to foliation; (e) Veinlet of quartz 3 crosscutting quartz 1 and quartz 2; (f) Quartz 1 fish and sulphides and oxides crystallised into micorshear planes.
Metamorphic petrology photomicrographs. All images are in plane-polarized light unless specified. (a) Vesicles filled with intergrowths of quartz, chlorite, and muscovite. Chlorite forming in pressure shadows. (b) Large calcite crystal. (c) Anomalous blue color in chlorite in cross-polarized light. (d) Epidote crystal with allanite veins. (e) Titanite crystals in the matrix and within an iron oxide crystal. (f) Abundant iron oxide in the matrix. alb: albite, aln: allanite, chl: chlorite, ep: epidote, ms: muscovite, qtz:quartz, ttn: titanite.
Thin section photomicrographs: A) monocrystalline quartz and plagioclase grains with albite twining; B) coarse microcline grain; C) detrital metamorphic rock grain; D) detrital volcanic rock grain; E) detrital sedimentary rock grain (chert); F) 2 flakes of biotite between the feldspar and quartz grains.
Quartz grains
Quartz grains are poorly sorted, fine to coarse, subrounded to subangular, and cemented together by slightly iron oxides and silica cement or by calcite cement (El Maghara sandstones containing calcareous quartz arenite).
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