What is the difference between plagioclase and feldspar

The plagioclase feldspars represent the "continuous branch" of Bowen's Reaction Series , and form a complete series between anorthite the pure calcium member , and albite the sodium-rich variety. This is quite a number, and since feldspar is nearly always present in igneous rocks, most classification schemes depend on the amount and kind of feldspar. In general terms, mafic and intermediate rocks contain plagioclase, with the more calcium present, the more mafic the resulting rock.

Orthoclase occurs only in the felsic igneous rocks. So if we're faced with the need to name an igneous rock, it is important to be able to distinguish between plagioclase and orthoclase. We can, however, make an educated guess in the field based on several assumptions, and a few easily identifiable physical features - color and the presence or absence of "striations.

The other k-spar minerals are sanidine, microcline and anorthoclase. Orthoclase is the more common of the k-spars. The differences between these minerals are minor in hand samples. Also Know, is potassium feldspar the same as orthoclase? Potassium feldspar. Potassium feldspar refers to a number of minerals in the feldspar group, and containing potassium : Orthoclase endmember formula K AlSi 3 O 8 , an important tectosilicate mineral that forms igneous rock.

Microcline, chemically the same as orthoclase , but with a different crystalline structure. Also Know, what is the most effective way to differentiate between potassium feldspar and plagioclase feldspar? Some cleavage planes of plagioclase feldspars have striations, whereas no potassium feldspars have striations.

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. Asked by: Laziz Labeke asked in category: General Last Updated: 25th May, What is the difference between plagioclase feldspar and potassium feldspar?

In general, potassium feldspars commonly have pink to reddish hues, while the plagioclase feldspars tend to be white or gray, but both mineral groups may exhibit similar colors, so the presence or absence of striations is more diagnostic. What are the two main types of feldspar? The feldspars are divided into two main groups: Potassium feldspar "K-spar" and plagioclase "plag".

What are the types of feldspar? The alkali feldspars include orthoclase, microcline, sanidine, anorthoclase, and the two-phase intermixtures called perthite.

The plagioclase feldspars include members of the albite-anorthite solid-solution series. Several meteorites have been found on Earth that are thought to be pieces of Mars. They are thought to be pieces of Martian bedrock, ejected beyond the influence of the planet's gravity by a large asteroid impact.

Some of these meteorites contain abundant plagioclase. Home » Minerals » Plagioclase Plagioclase A group of common rock-forming minerals. It is sometimes used as a gem material. Article by: Hobart M. Also colorless, yellow, orange, pink, red, brown, black, blue, green. Streak White Luster Vitreous. Pearly on some cleavage faces. Diaphaneity Translucent to transparent Cleavage Perfect in two directions that intersect at approximately 90 degrees. Mohs Hardness 6 to 6.

Well-defined crystals are extremely rare. Labradorite, spectrolite, sunstone, and moonstone are gem-quality plagioclase feldspars that are popular because of their optical phenomena. Transparent plagioclase of high clarity is sometimes faceted as a collector gem but lacks the durability needed for use in jewelry.

Find Other Topics on Geology. Maps Volcanoes World Maps. Usually white or gray. Perfect cleavage, with cleavage faces intersecting at right angles and striations often present on cleavage faces. Plagioclase feldspars are important components of many building stones.

Rock and Mineral Kits. Are Water and Ice Minerals? Mohs Hardness Scale. Hardness Picks. Rocks: Galleries of igneous, sedimentary and metamorphic rock photos with descriptions. Minerals: Information about ore minerals, gem materials and rock-forming minerals.

Volcanoes: Articles about volcanoes, volcanic hazards and eruptions past and present. Gemstones: Colorful images and articles about diamonds and colored stones. General Geology: Articles about geysers, maars, deltas, rifts, salt domes, water, and much more! Geology Store: Hammers, field bags, hand lenses, maps, books, hardness picks, gold pans. Earth Science Records: Highest mountain, deepest lake, biggest tsunami and more.