Bitotie Granite Isotropic Or Anisotropic

Sometimes we call muscovite as white mica and biotite as black mica.

Bitotie granite isotropic or anisotropic.

Anisotropic gems anisotropy anisotropism. The key difference between muscovite and biotite is that muscovite contains mainly potassium and aluminium while biotite mainly contains potassium and magnesium. Large grains or fine fibrous masses of hornblende may mantle or replace pyroxene. They have many similarities as well as some differences.

The simple definition of anisotropy or less commonly anisotropism is exhibiting different values of a particular property of a material when measured in different directions as opposed to isotropy. Granite gneiss migmatite biotite m hornblende gneiss q quartzite quartz schist su gneiss schist complex bs biotite garnet schist. The odds of a grain lying in just the. The mineral grain size of laurentian granite varies from 0 2 to 2 mm with the average quartz grain size of 0 5 mm and the average feldspar grain size of 0 4 mm with feldspar being the dominant mineral 60 followed by quartz 33.

Grains may be bent particularly in metamorphic rocks. Commonly found as slender prismatic to bladed crystals with a diamon shaped cross section showing the amphibole cleavage at 56 and 124. A very simple example of anisotropy is wood. Euhedral crystals are not uncommon are usually tabular parallel to 001 and have a roughly hexagonal cross section.

A complication arises because anisotropic minerals will appear isotropic if grains are oriented in a specific way if they are oriented so they are viewed down an optic axis additionally as the microscope stage is rotated anisotropic minerals in any orientation go extinct turn black every 90 o. Muscovite and biotite are phyllosilicate minerals. More aluminous end members include siderophyllite and eastonite biotite was regarded as a mineral species by the international. Especially biotite can contribute to the bulk rock elastic anisotropy significantly kern wenk 1990 as shows its single crystal elastic anisotropy of 44 per cent simmons wang 1971.

This patch of biotite shows a range of pleochroic colors caused by different crystal orientations. Also found as anhedral to strongly irregular grains which in some cases may poikilitically enclose associated minerals. Biotite is a common group of phyllosilicate minerals within the mica group with the approximate chemical formula k mg fe 3 alsi 3 o 10 f oh 2 it is primarily a solid solution series between the iron endmember annite and the magnesium endmember phlogopite. In addition to cpo biotite and muscovite spo has been found to contribute significantly to the bulk rock elastic anisotropy kern et al 2009.

Also found as micaceous or tabular grains or grains with irregular outline. Anisotropic if the value of a vector measurement of its resistivity varies with direction taylor and flemming.