What is the chemical formula for plagioclase feldspar?
| Plagioclase | |
|---|---|
| Category | Feldspar mineral group, tectosilicate |
| Formula (repeating unit) | NaAlSi3O8 – CaAl2Si2O8 |
| Crystal system | Triclinic |
| Crystal class | Pinacoidal (1) (same H-M symbol) |
What is the chemical composition of plagioclase?
| Physical Properties of Plagioclase | |
|---|---|
| Chemical Classification | Silicate |
| Specific Gravity | 2.6 to 2.8 |
| Diagnostic Properties | Perfect cleavage, with cleavage faces intersecting at right angles and striations often present on cleavage faces. Well-defined crystals are extremely rare. |
| Chemical Composition | NaAlSi3O8 – CaAl2Si2O8 |
What is sodic plagioclase?
About Sodic plagioclaseHide A petrological term for plagioclase feldspars dominant in sodium. In pure mineralogical terms the name albite would be synonymous.
What type of silicate is plagioclase?
framework silicate
Plagioclase is a member of the feldspar group (like orthoclase) and is a framework silicate. Plagioclase consists of a solid solution between the albite and anorthite end-members, and together with quartz is the most common of the rock forming minerals.
What rock is plagioclase?
igneous rocks
Plagioclase is found in almost all igneous rocks and most metamorphic rocks, but is less common in sedimentary rocks where it usually weathers to clay minerals or a fine grained variant of muscovite (sericite).
What is the sodic plagioclase?
What causes plagioclase?
Each plagioclase grain is made up of stacks of thin crystal with their molecules arranged in opposite directions. This causes the cleavage planes to have fine parallel line across them called striations.
What is plagioclase feldspar used for?
Plagioclase is used in the manufacture of glass and ceramics; the iridescent varieties peristerite and labradorite are valued as gemstones or ornamental material. The primary importance of plagioclase, however, derives from its role in rock formation.
What does the word plagioclase mean?
: a triclinic feldspar especially : one having calcium or sodium in its composition.
How many cations are in plagioclase?
Stoichiometry. There are five cations per formula unit: four tetrahedra and one large cation site. Na + Ca (+ K) should sum to 1.
What is plagioclase used for?
Plagioclase is used in the manufacture of glass and ceramics; the iridescent varieties peristerite and labradorite are valued as gemstones or ornamental material.
Is plagioclase a mineral?
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more properly known as the plagioclase feldspar series…
Is feldspar a silicate or a non silicate mineral?
The vast majority of the minerals that make up the rocks of Earth’s crust are silicate minerals. These include minerals such as quartz, feldspar, mica, amphibole, pyroxene, olivine, and a variety of clay minerals.
What is the chemical formula for potassium feldspar?
Chemical composition. All the rock-forming feldspars are aluminosilicate minerals with the general formula AT4O8 in which A = potassium, sodium, or calcium (Ca); and T = silicon (Si) and aluminum (Al), with a Si:Al ratio ranging from 3:1 to 1:1. Microcline and orthoclase are potassium feldspars (KAlSi 3 O 8 ),…