oligoclase thin section

This item will ship to United States, but … Oligoclase is about 90-70% Albite and 10-30% Anorthite. 00023. Albite is the sodium-rich end member while Anorthite is the Plagioclase - NaAlSi 3 O 8--CaAl 2 Si 2 O 8 Plagioclase feldspars are the most common feldspar minerals because calcium is somewhat more common in the crust than potassium (3.6 and 2.8 percent of the crust, respectively). Oligoclase is a somewhat rare variety of Albite and a member of the Plagioclase Feldspars of the Feldspar Group of minerals that includes Albite, Amazonite, Andesine, Anorthite, Bytownite, Hyalophane, Labradorite, Moonstone,Oligoclase, Orthoclase, Sanidine and Sunstone. Labradorite can display an iridescent optical effect (or schiller) known as labradorescence. Alex Strekeisen - I vetrini della mia fantasia. Alex Strekeisen - I vetrini della mia fantasia. The cause of this optical phenomenon is lamellar structure caused by an exsolution process due to a miscibility gap. The Plagioclase Feldspars form a series between Albite and Anorthite. Sericite #2 thin section (hFOV 2mm) GET 360° LIVE INTERACTION. Labradorite Na0:5¡0:3Ca0:5¡0:7Al1:5¡1:7Si2:5¡2:3O8 °c 2001 Mineral Data Publishing, version 1.2 Crystal Data: Triclinic. Usually found as micaceous flakes or tablets with irregular outlines, tabular parallel to {001}. Rhyolite Rhyolite: A collective term for silicic volcanic rocks consisting of phenocrysts of quartz and alkali feldspar, often with minor plagioclase and biotite, in a microcrystalline or glassy groundmass and having the chemical composition of granite. Cleavages intersect at 90°. Has perfect cleavage on {001} and good cleavage on {010}. 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. An intermediate member of the Albite-Anorthite Series. It had previously been recognized as a distinct species by J. J. Berzelius in 1824. A variety of Anorthite A plagioclase feldspar with an albite : anorthite molar ratio ranging from 30 : 70 to 50 : 50. Oligoclase was named in 1826 by August Breithaupt from the Greek words όλίγος and κλάσις meaning little and to break because the mineral was thought to have a less perfect cleavage than Albite. Shipping and handling. It can be difficult to see cleavage in thin section due to orthoclase’s low relief. Relief: Low-Moderate positive Habit/Form: Well-formed tabular crystals with a roughly hexagonal outline are rare. Sericite PPL properties. Seller assumes all responsibility for this listing. Thin-section mount of oligoclase (triclinie) from Arendal, Norway, petrographic microscope slide. For viewing under polarized or transmitted light.

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