Perthite is used to describe an intergrowth of two feldspars: a host grain of potassium-rich alkali feldspar (near K-feldspar, KAlSi3O8, in composition)...
3 KB (335 words) - 14:34, 20 January 2024
Sanidine is stable at the highest temperatures, and microcline at the lowest. Perthite is a typical texture in alkali feldspar, due to exsolution of contrasting...
25 KB (2,434 words) - 22:46, 14 June 2024
charnockite series, consisting essentially of quartz, antiperthite (or perthite), orthopyroxene (usually hypersthene) and magnetite, and is equivalent...
749 bytes (62 words) - 14:12, 27 July 2023
with potassium. The resulting intergrowth of the two feldspars is called perthite. The higher-temperature polymorph of KAlSi3O8 is sanidine. Sanidine is...
8 KB (598 words) - 04:23, 14 September 2024
Pahangite (also "Pahangese") Patna → Patnaites Penang → Penangite Perth → Perthites (also "Perthian" and "Perthling") Pullman → Pullmanites Putney → Putneyites...
63 KB (2,055 words) - 13:18, 14 September 2024
"Dalmatian jasper" – not a jasper at all but a form of the igneous rock perthite. The black spots are composed of the rare amphibole arfvedsonite (and not...
19 KB (1,734 words) - 06:17, 26 July 2024
Papagoite Pargasite Parisite Pectolite Larimar Pentlandite Peridot Periclase Perthite Petalite (castorite) Pezzottaite Phenakite Phlogopite Phosgenite Phosphophyllite...
13 KB (867 words) - 01:34, 24 August 2024
feldspars. The feldspar has partly unmixed on the micro-scale to form a perthite, and the presence of the alternating alkali feldspar and plagioclase layers...
5 KB (441 words) - 11:17, 14 March 2023
occurs as fine parallel segregations alternating with pink microcline in perthite as a result of exolution on cooling. There are two variants of albite,...
7 KB (561 words) - 16:13, 8 July 2024
multiple twinning which forms a grating-like structure that is unmistakable. Perthite is either microcline or orthoclase with thin lamellae of exsolved albite...
8 KB (660 words) - 16:54, 11 September 2024
commonly represented by orthoclase and the exsolved lamellar albite, form perthite. In some rocks the potash feldspar, in others the soda feldspar predominates...
18 KB (2,131 words) - 15:06, 22 April 2023
intrusive rock, which consists essentially of alkali-feldspar (orthoclase, perthite, anorthoclase, and albite). Some samples may contain a small amount of...
2 KB (241 words) - 13:09, 9 May 2020
composition alkali feldspars are allowed to cool slowly, exsolution occurs and a perthite structure results. Anorthoclase occurs in high temperature sodium rich...
5 KB (306 words) - 17:50, 2 November 2023
as biotite granite: pink coarse-grained leucocratic; contains quartz, perthite, oligoclase, biotite and accessory apatite and zircon; veins of aplite...
8 KB (750 words) - 07:27, 17 July 2024
layers will alternate between typically pink microcline, resulting in a perthite texture. Solid solution strengthening Abbaschian, Reza; Reed-Hill, Robert...
15 KB (1,855 words) - 01:00, 12 April 2024
Myrmekite replacing K-feldspar in perthite during Na-Ca-metasomatism, showing isolated quartz vermicules of irregular shape. Lyon Mountain granite gneiss...
12 KB (1,508 words) - 14:21, 29 September 2023
of plagioclase (lamellae) are present in potassium feldspar, is called perthite. The solid solution between anorthite and albite remains stable to lower...
25 KB (2,886 words) - 02:59, 25 August 2024
Mount Desert Island bedrock consists mainly of Cadillac Mountain granite. Perthite gives the granite its pinkish color. The Silurian age granite ranges from...
103 KB (9,903 words) - 14:33, 6 September 2024
Pescarese Pescarese Perth Perthert, Perthite, Perthian, Perthling, Perthonality, Pertho, Perthie Perthert, Perthite, Perthian, Perthling, Perthonality...
49 KB (779 words) - 20:43, 8 September 2024
to coarse-grained and moderately foliated containing minerals such as perthite, quartz, hornblende with accessory biotite, opaques, apatite, and zircon...
5 KB (429 words) - 13:41, 2 May 2022
known as hypersthene). The alkali feldspars in the group are generally perthites, with intergrowths of albite and orthoclase or microcline, while the plagioclases...
9 KB (1,053 words) - 07:40, 30 April 2024
form by exsolution are aids in interpreting cooling histories of rocks. Perthite is an intergrowth of K-feldspar with albite feldspar, formed by exsolution...
18 KB (2,304 words) - 09:40, 23 September 2023
University of Chicago in 1948. His Ph.D. thesis was titled Petrogenesis of Perthite Pegmatites in the Btoch Hills, South Dakota. He received his D.Sc. in Geology...
3 KB (254 words) - 22:12, 21 March 2024
feldspathoid minerals. In the acid rocks, the common feldspars are orthoclase, perthite, microcline, and oligoclase—all having much silica and alkalis. In the...
57 KB (7,059 words) - 22:35, 1 September 2024
such as charnockite granulites, gneiss, hornblende schist and biotite. Perthite gneisses and granulites formed in areas with isoclinal folding. The Mchinji...
8 KB (1,061 words) - 09:08, 14 July 2024
syenite gneiss (mainly litchfieldite): nepheline, albite, microcline, perthite, dark green biotite, (calcite), (white mica), (zircon), (pyrochlore), (cancrinite)...
9 KB (1,023 words) - 11:04, 14 March 2023
evidence of hydrothermal fluid alteration, including coarse-patch perthite, perthite crystals with albite rims, and the recrystallization of mafic minerals...
12 KB (1,620 words) - 21:54, 12 July 2023
within the Concord complex is made up of coarse-grained phenocrysts of perthite that are surrounded by other various minerals such as: Plagioclase Microcline...
7 KB (742 words) - 16:39, 7 June 2024
Plagioclase displays zonation and albite twinning. Potassium feldspar can show perthite textures, carlsbad twinning, and, in microcline, tartan twinning. Quartz...
10 KB (1,374 words) - 16:19, 11 February 2023
gives rise to multiple forms of unmixing products, e.g. various kinds of perthite. "Due to slow reaction kinetics, feldspars usually do not attain equilibrium...
3 KB (334 words) - 14:17, 20 November 2023