Peraluminous two-mica granitoid. See the answer. Hausmann named the mineral biotite in honor of French physicist Jean-Baptiste Biot, who explored the optical properties of mica. Optic Colour This is the colour of the mineral as seen through the microscope. Named in 1847 by Johann Friedrich Ludwig Hausmann in honour of the French physicist, mathematician, meteoriticist, astronomer, and mineralogist, Jean-Baptiste Biot [April 21, 1774, Paris, France - February 3, 1862, Paris, France], who studied the optical properties of the micas. Biotite was named by J.F.L. White Light, or visible light, is a form of electromagnetic radiation (energy waves produced by the motion of an electric charge). Several important optical properties are applicable to minerals and gemstones, and can be very useful for gem identification. Biotite is a sheet silicate; iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. Optical Properties: PPL: Brown, green, or reddish color Strong brown, yellowish brown, or greenish brown pleochroism ... Brown, red, or green color: δ: 0.04: Twinning: None: Extinction: Birdseye Parallel or near-parallel: after Perkins, 321: Biotite in Hand Sample. There is ⦠Biotite is a sheet silicate. Biotite, a silicate mineral in the common mica group. Biotite (thin section) View Description. Many minerals in the Earth's crust are silicates , but mica is distinct in the way it ⦠In metamorphic rocks, biotite usually shows a preferred orientation with its {001} forms parallel to the schistose foliation. Typically, however, biotiteâs dark color prohibits such a mistake. For chemical formula and detailed physical properties, see mica (table). Home Rocks and Minerals Biotite (thin section) Reference URL Share . It is named in honor Jean Baptiste Biot (1774 - 1862), a French physicist, mathematician, and astronomer who researched the mica minerals for their optical properties. It is named in honor Jean Baptiste Biot (1774 - 1862), a French physicist, mathematician, and astronomer who researched the mica minerals for their optical properties. Biotite and muscovite are the two most common mica minerals that often occur together in Al-rich igneous rock. Distinguished from phlogopite by not being decomposed in sulfuric acid and from lepidolite by not giving a crimson flame. Name Origin: Named in 1847 after the French physicist, Jean Baptiste Biot (1774 - 1862), who studied the optical properties of the micas. Biot +â -ite, named by J.F.L. It is one of the most strongly colored minerals seen in thin section under a microscope. Biotite hand-specimen Formula: K(Mg,Fe) 3 (AlSi 3 O 10 )(F,OH) 2 The name "biotite" is used in the field and in entry-level geology courses because these minerals generally cannot be distinguished without optical, chemical, or x-ray analysis. The mineral streak of biotite is white. You will find links to your left on general information, composition and chemical formula, optical properties, physical properties⦠In the XP view, the biotite interference colors range up to 2nd order red (with just a hint of 2nd order blue). In thin section, it shows the perfect cleavage and ⦠Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. Diagnostic Features: Characterized by its highly perfect cleavage and light color. Biotite Optical Mineralogy. Such exsolution textures are most readily observed in cross polars as host and exsolved minerals often have rather similar optical properties and so may have similar relief. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. The largest grain of biotite contains a pelochroic halo (burn mark) around an included zircon. Airn, magnesium, aluminium, silicon, oxygen, an hydrogen furm sheets that are waikly boond thegither bi potassium ions. IPA : /ËbaɪÉËtaɪt/ Noun . Moreover, its optical properties can vary from transparent to translucent to opaque. The optical properties that can be seen under this arrangement are as follows, 1. Prices / ⦠Biotite is a very common form of mica. This large book of biotite (~ 6" across) shows the 6-sided shape of perfect biotite crystals. Common biotite can show shades of brown yellow green and red. Biotite was named by J.F.L. The minerals listed below are those which are introduced in ERSC 2P22 â Optical Mineralogy and 3P21 â Petrology and Petrography at Brock. Also, the tenacity of biotite is brittle to flexible.