Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg 3 AlSi 3 O 10 (F,OH) 2. Chemical Formula: KMg 3 (AlSi 3 O 10)(OH,F) 2 Name Origin: From the Greek flogopos â âresembling fire.âPhlogopite is a yellow, greenish, or reddish-brown member of the mica family of phyllosilicates. Question: Describe How The Optical Properties Of Phlogopite Different Than Biotite. See the answer. It has a smaller 2V than muscovite and is often col-ored light brown. Expert Answer . Phlogopite occurs typically as a metamorphic product (e.g., in crystalline metamorphosed limestones) and also in ultramafic igneous rocks. Optical Properties: Previous question Next question Get more help from Chegg. Cliemical Composition. Chocolate consists of cocoa butter, cocoa particles, sugar, and additives, which together determine its taste and optical properties. K(Mg,Fe) 3 AlSi 3 O 10 (OH) 2 Phlogopite refers to micas at the magnesian end (Mg/(Mg+Fe) > 0.67) of the biotite-phlogopite solid solution series.Phlogopite has many of the optical characteristics of biotite, with the most important difference being that phlogopites are less strongly coloured (i.e., the pleochroic colours are not as intense). Optical Properties : Phlogopite is similar to other micas in thin section. Main members â phlogopite (KMg 3 (AlSi 3 O 10) (OH) 2) as Mg end-member, annite (K Fe 3 2 + (AlSi 3 O 10) (OH) 2) as Fe end-member. It is also known as magnesium mica.Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg 3 (AlSi 3 O 10)(OH,F) 2. Phlogopite, like other Micas, has a layered structure which produces its perfect cleavage. Phlogopite. Nearly pure phlogopite is found in hydrous ultrabasic rocks like kimberlite, and is also found in metamorphosed dolomites. Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg 3 AlSi 3 O 10 (F,OH) 2.Iron substitutes for magnesium in variable amounts leading to the more common biotite with higher iron content. Biotite, with more Fe-rich compositions is common in dacitic, rhyolitic, and trachytic volcanic rocks, granitic plutonic rocks, and a wide variety of metamorphic rocks. Phlogopite is rarely considered a valuable mineral specimen and is ⦠The darker color and density increase with an increase in the iron content. For physical and optical identification, it shares most of the characteristic properties of biotite. It may be pleochroic, but not as much as the Fe-rich biotites. The optical properties of chocolate play a vital role in consumer perception, representing type and quality in the blink of an eye. Phlogopite is iron poor and Biotite is iron rich. For physical and optical identification, it shares most of the characteristic properties of biotite. Describe how the optical properties of phlogopite different than biotite. Optical properties of the phlogopite are summarized in Table 1. This problem has been solved! For physical and optical identification, it shares most of the characteristic properties of biotite. Biaxial 1- 2, a = 1.56, b = 1.60, g = 1.60, d = 0.04, 2V = 0° to 20°. Iron substitutes for magnesium in variable amounts leading to the more common biotite with higher iron content.