White Mica: Properties, Applications and Prospects
Jun. 04, 2021
White Mica is the most common mineral in the mica family. It is an important rock-forming mineral, found in igneous, metamorphic and sedimentary rocks. Like other mica, it readily cleaves into transparent flakes. Muscovite flakes have a pearly to glassy luster on their surface. If held up to the light, they are transparent and almost colorless, but most have a slight brown, yellow, green or rose tint.
Dolomite's ability to split into clear sheets - sometimes up to several feet wide - led to its early use as window glass. in the 17th century, people mined pegmatites from the area around Moscow, Russia, for this purpose. These window panes were known as "Muscovy glass," a term thought to have inspired the mineral name "Muscovite.
Flake dolomite is an excellent insulator, which makes it suitable for the manufacture of specialized components for electrical equipment. Scrap, flakes and ground dolomite are used as fillers and extenders in a variety of coatings, finishes and manufactured products. Muscovite's pearly luster makes it an important ingredient for adding "sparkle" to paints, ceramic glazes and cosmetics.
Muscoviteis easily identified by its perfect cleavage that allows it to be divided into thin, flexible, flexible, colorless, transparent flakes with a pearly to glassy luster. It is the only common mineral with these properties.
An important rock-forming mineral
Limonite is found in igneous, metamorphic and sedimentary rocks. In igneous rocks, it is a primary mineral and is particularly common in granitic rocks. In granitic pegmatites, leucite often occurs as large crystals with a pseudo-hexagonal outline. These crystals are called "books" because they can be divided into paper-thin sheets. Limonite rarely occurs in igneous rocks of intermediate, smectite and ultramafic compositions.
Limonite can form during regional metamorphism of the concentrate rocks. The heat and pressure of metamorphism converts clay minerals into tiny mica grains, which expand as metamorphism proceeds. Mica can occur as isolated grains in schists and gneisses, or it can be abundant enough for the rock to be called "mica schist" or "mica gneiss".
Mica is not particularly resistant to chemical weathering. It is quickly converted to clay minerals. Tiny mica flakes sometimes survive long enough. It proves that these sediments and rocks were not weathered. These sediments and rocks have not been subjected to severe weathering.
Uses of flake mica
While ground mica may sell for as much as $300 per ton, sheet mica used for special purposes can sell for as much as $2,000 per kilogram. Mica has several properties that make it suitable for very specific uses.
1) It can be split into thin flakes
2) The flakes are chemically inert, dielectric, elastic, flexible, hydrophilic, insulating, lightweight, reflective, refractive and resilient
3) It is stable when exposed to electricity, light, moisture and extreme temperatures.
Most mica flakes are used in the manufacture of electronic devices. In these applications, mica sheets are cut, punched, stamped and machined to exact dimensions. Uses include: diaphragms for oxygen breathing equipment, marker discs for navigation compasses, optical filters, pyrometers, retardation plates for He-Ne lasers, missile system components, medical electronics, optical instruments, radar systems, radiation detector windows, and calibration capacitors.
The use of ground mica is largely determined by the level of activity in the construction and automotive industries. Increased domestic oil and gas drilling should sustain demand for mica additives to drilling muds. U.S. producers should be able to supply domestic demand, with some mica being imported for special applications or being more expensive to ship from domestic producers to consumers than imported mica.
Although the demand for mica flakes is growing as technology advances, the price is so high that alternative materials are increasingly being invented. Some of these involve making mica flakes from ground up mica composites or creating synthetic mica in the laboratory. Acrylic, fiberglass, nylon, polyester, styrene, vinyl-polyvinyl chloride, and vulcanized fibers have all been used as substitutes for Mica Flakes.
Phlogopite is a common member of the mica mineral group. Its chemical composition is KMg32. The crystals of Phlogopite are usually brown, but can be yellow, green or reddish brown. It is sometimes referred to as "brown mica"...