Granite Thin Section
Anthophyllite thin section
Relief: Moderate positive Habit/Form: Commonly found as euhedral to subhedral columnar, bladed, or acicular crystals, with diamond-shaped cross section typical of amphiboles. Sometimes found as fine to coarse radiating aggregates. There also is an asbestiform variety. Color: Colorless, clove-brown (Fe), yellowish brown (Fe), grayish brown (Fe), …
Brucite thin section
Isotropy/Anisotropy: Anisotropic Interference color: Order I; Some of the interference colors are anomalous; a pelicular reddish brown hue takes the place of the yellow and orange of the first order. If the section is too thin, the anomalous colors do not show. Extinction angle: Parallel / 0° / straight to cleavages or fibers. Twins: Absent Uniaxial/Biaxial: …
Photographs of granite porphyry (a); and thin …
Download scientific diagram | Photographs of granite porphyry (a); and thin section photomicrographs of representative rhyolite porphyry (b), granite porphyry (c), and quartz porphyry (d); e ...
Granite – Loch Doon
In thin section the granite contains coarse grained plagioclase, quartz, and orthoclase grains which exhibit perthite exsolution textures. The larger grains are surrounded by smaller polygonal grains of quartz and …
Spodumene thin section
Relief: Moderate-High positive Habit/Form: Crystals are prismatic with roughly octagonal cross sections that show both cleavages intersecting at about 87°. Also as lathlike acicular crystals and cleavable masses. Because spodumene is usually found in pegmatites, its crystals may be far larger than normal in thin sections.
Augite thin section
Isotropy/Anisotropy: Anisotropic Interference color: Order I-II; bright Extinction angle: The maximum extinction angle of longitudinal sections varies from 35° to 45°. These sections have the maximum interference colors for the slide. Some varieties have a peculiar concentric wavy extinction known as the hourglass structure.
Sodalite thin section
Habit/Form: Crystals are dodecahedra, which in thin section show six-sided cross section. Sodalite is often anhedral in plutonic rocks. Sodalite is often anhedral in plutonic rocks. Symmetrically or zonally arranged inclusions are common in nosean and hauynite.
16 Photo Gallery of Rocks in Hand Specimen and …
16.5 Biotite-hornblende granite; 8.5 cm across: 16.6 Thin section (PP) view of the same granite; 2.5 mm across: 16.7 Thin section (XP) view of the same granite blank space: ⇒Link to 3D rotatable image of this …
Virtual Microscope
The Virtual Microscope – Ore Minerals is a professional and interactive virtual petrographic microscope which allows geologists to examine and explore minerals and their microscopic features.. The Virtual Microscope – Ore Minerals makes Optical Mineralogy easier to examine a polished section and to understand the characteristic properties of …
5.7: Identifying Minerals and Mineral Properties in Thin Section
This page titled 5.7: Identifying Minerals and Mineral Properties in Thin Section is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or …
Kyanite thin section
Relief: High positive Habit/Form: Kyanite commonly forms elongate bladed or columnar crystals that may appear to be bent. It is rarely fibrous. Color: Colorless to pale blue; violet blue (thick section), cobalt blue (thick …
Granite
The Shap granite, a distinctive coarse-grained granite with large pink orthoclase feldspar, was intruded late in the Caledonian orogeny around 394 million years ago. ... The large …
I05. Granite
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, …
Biotite granite
The thin section contains large plates of biotite showing alteration to chlorite, with lesser amounts of equally sized muscovite. Large plates of quartz show little deformation, orthoclase and plagioclase feldspar are both altered, plagioclase exhibits compositional zoning and orthoclase exhibits coarse perthite textures.
The interpretation of granitic textures from serial thin …
The work highlights the important factors and potential problems in the use of serial thin sections and imaging in the analysis of complex polyphase rock textures. …
Microcline thin section
Microcline – from Greek for little and slanted, in reference to the slight variation of the cleavage angle from 90°. Feldspar (mineral group name), from Swedish names for field (feldt or falt) and spar (spat), in reference to the spar in tilled fields overlying granite; in German the word became Feldspat.
Graphic granite: Mineral information, data and localities.
An intergrowth of quartz and feldspar which may appear as runic or cuneiform writing (hence the term), as darker and glassier quartz 'characters' or 'letters' in a groundmass of white feldspar (usually microcline). This is found almost exclusively in granitic pegmatites, and is believed to result from simultaneous growth of the feldspar and quartz under …
Olivine thin section
Relief: Very High – High positive Habit/Form: In most metamorphic and intrusive igneous rocks, olivine tends to form subequant, anhedral grains or aggregates of grains. Euhedral crystals are more common in volcanic …
The interpretation of granitic textures from serial thin …
use of serial thin sections and imaging in the analysis of complex polyphase rock textures. KEYWORDS: texture, granite, image analysis, serial thin section, Peru. Introduction AN understanding of igneous rock textures is fundamental to the interpretation of magma chamber fluid dynamic and chemical processes, and
Bronzite thin section
Isotropy/Anisotropy: Anisotropic Interference color: Order I – II Extinction angle: Parallel / 0° / straight in longitudinal sections and symmetrical in basal sections Twins: Simple and lamellar twinning on {100} and {001} …
Graphic Texture
Graphic granite. Star Beach Granite, Brazil. Image from James St. John. Graphic granite. Amazon Gold Granite, Brazil. Image from James St. John. Graphic granite. Image from James St. John. Bibliography • Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
Rutile thin section
Isotropy/Anisotropy: Anisotropic Interference color: High-order cream (often is masked by colour); interference colors are very high but do not show well on account of total reflection. Extinction angle: Parallel / 0° / straight; difficult to detect due to extreme birefringence Twins: Rare; in large crystals. Uniaxial/Biaxial: Uniaxial (+) Optic axial angle (2V): –
Garnet thin section
Relief: High positive Habit/Form: Garnets commonly occur as euhedral to subhedral dodecahedral {110} or trapezohedral {112} crystalss, which in thin section yield six- or eight-sided cross sections. Garnet also occurs as granular or irregular masses. Color: Garnet group: nearly colorless to a pale-brown/pink/green. Almandine: nearly colorless, …
Granite
Click the microscope button to view a thin section for this sample. Microscope. Click the microscope button to view a thin section for this sample. ... Granite - Lundy. The Lundy granite complex is an anomaly as it looks very similar to the many of the granites of Cornwall (and Dartmoor), but yet is very much younger at 58.7±1.6 Ma. It is the ...
Riebeckite thin section
Isotropy/Anisotropy: Anisotropic Interference color: Order I red to order III green; the interference colors are masked by the deep blue color of the mineral. Extinction angle: The maximum extinction angle in elongate sections is about 0-8°, but the fibrous variety, crocidolite, has parallel extinction. Twins: Simple and lamellar twins on {100} …
Barite thin section
Relief: Moderate positive Habit/Form: Crystals are typically tabular or, less commonly, prismatic parallel to the a or b crystal axes. Crystals are often intergrown, forming rosettes or platy aggregates. Barite also forms concretionary masses with fibrous texture, and granular or cleavable masses.
Diopside thin section
Relief: High positive Habit/Form: Crystals are usually stubby prisms elongate along the c axis. Basal cross sections are four or eight sided and show the two cleavages at ~87°. Longitudinal sections are roughly rectangular and show only one cleavage direction.
Granite
Click the microscope button to view a thin section for this sample. Microscope. Click the microscope button to view a thin section for this sample. ... Granite - Shap. The Shap granite, a distinctive coarse-grained granite with large pink orthoclase feldspar, was intruded late in the Caledonian orogeny around 394 million years ago. The granite ...
Granite – Loch Doon
In thin section the granite contains coarse grained plagioclase, quartz, and orthoclase grains which exhibit perthite exsolution textures. The larger grains are surrounded by smaller polygonal grains of quartz and feldspar that appear to indicate late stage recrystallisation. Smaller grains of biotite mica is also present in the section and a ...
Granite TS
Granite Thin Section Photos. Click on any photo for a larger image. Some of the larger images may be on other web sites and will open in a new window. Return to granite Page Hand Samples Phase Maps. grnts_001. Muscovite-biotite granite from Concord, NH, USA (Concord Granite). Wards Collection of North American rocks, Smith College sample (W …
Minerals and Rocks under the microscope
The study of rocks in thin section is the most effective way of giving the undergraduate or graduate student a true realization of the mineralogical constitution of rocks. Not until he …
Rocks in thin section
This video shows a thin section of a rock made of quartz, muscovite mica, biotite mica and garnet. The properties of the main rock-forming minerals as seen under a polarising light microscope are described. Images in this …
The interpretation of granitic textures from serial thin …
FIG. 2 Plagioclase geometries f om six erial sections through the Arequipa granodiorite ofthe Peruvian Co stal Batholith. The distance between each of the sections …
Titanite (Sphene) thin section
Relief: Very High positive Habit/Form: Euhedral to subhedral grains with a wedge- or diamond-shaped cross section are common, as are rounded or irregular anhedral grains. Radioactive varieties may form pleochroic halos in enclosing biotite, chlorite, or hornblende. Color: Almost colorless to neutral; tan-brown color or yellow-brown Pleochroism: Absent …
I05. Granite
Granite. Collection: Irish Universities GeoLab. Click the microscope button to view a thin section for this sample. Microscope. Click the microscope button to view a thin section for this sample. Microscope. Fact sheet. …
Granite
Granite. Granite is a medium-tocoarse-grained acid igneous rock with essential quartz (>20%) and feldspar, where alkali feldspar constitutes between 100 and 35% of the feldspars, and minor mafic minerals. …
Plagioclase thin section
Relief: Low-moderate negative/positive (Albite-Anorthite series) Habit/Form: Plagioclase commonly occurs both as euhedral and anhedral grains. Crystals are usually tabular parallel to (010) and elongate parallel to the c or a axis. Cross sections are more or less rectangular. Color: Colorless, frequently cloudy due to incipient alteration Pleochroism: