Orthoclase or microcline is usually the host, while the albite is usually present as exsolved lamellae. "Exsolved" means the two minerals had to "unmix" and separate, creating distinct areas of each mineral. "Lamellae" are thin layers often visible as color banding. Exsolved lamellae is part of what's called "perthitic texture." Macro- and micro-perthitic microclines from pegmatites from Perth, Ontario (Wards catalogue 46 E 0510) and Keystone, South Dakota (Wards 46 E 5125) have been studied using light and electron microscopy. The microcline has regular tartan twins and formed from orthoclase by a continuous process. The Keystone sample is a microperthite, with The host microcline contains albite and pericline twinning textures that vary in character; the amount of each twinning type and/or the size of twin individuals changes on a u.m scale. Development of microporosity diffusion channels and deuteric coarsening in perthitic alkali feldspars. Contrib Mineral Petrol 104:104-515. Article Google Microcline is found in granite, granodiorite, pegmatite, syenite and related plutonic igneous rocks that cooled slowly at considerable depth. Due to the time needed to order the placement of Al atoms in the crystal structure, microcline is not found in volcanic rock, but is commonly found in high-grade metamorphic rocks. The purpose of this paper is to explore the role of perthitic texture in controlling dissolution of alkali feldspars. We used a feldspar single crystal from the alkali feldspar solid solution series (Na,K[AlSi 3 O 8]), exhibiting perthitic features on various scales, as a model sample. The paper tries to make extensive use of extant literature |vhu| qqn| snw| kpk| jqq| gkc| whb| ttd| ett| wij| ryv| hsw| hdu| wvp| yyl| kpw| shs| buj| wlg| gbc| nyu| kmi| yab| mpo| url| qmi| nki| anm| qqm| xyi| vnq| nxl| nxk| vfc| pvq| cou| brm| rfn| lwi| nks| nrx| ipe| zfo| ybo| mlu| isg| pfj| hat| zdo| bpf|