X represents large interlayer cations, such as K+, Na+, Ca2+, Ba2+, Rb+, Cs+, etc. Y represents octahedral cations, such as Al3+, Fe2+, Mg2+, Cr3+, Ti4+, Fe3+, etc. Z is mainly Si4+ and Al3+; The ideal ratio of the additional anion (OH)- to (O)2- is 2:10, and (OH)- can be replaced by F- and Cl-. Most mica contain 4% to 5% water. Therefore, although they may be called mica, the chemical composition of different mica may be very different, for the purpose of research, we collectively refer to the minerals with this type of characteristics as mica group minerals.  

Pigment powders are finely ground colored particles that are used to impart color to various materials, including paints, plastics, and resins. Unlike dyes, which dissolve in the medium, pigments are particulate solids that remain suspended within the material. This unique property ensures that the color remains stable and does not degrade over time, making pigments an essential choice for long-lasting applications.

Natural mica powder and synthetic mica powder have differences in production methods, heat resistance and color transparency. As the name suggests, natural mica powder is made from natural mica ore after processing, retaining the original characteristics and composition of the ore. Its main components are SiO2 (about 49%) and Al2O3 (about 30%), while also containing K2O+Na2O (9%-11%) and so on. The synthetic mica powder (such as fluoroglogopicite powder), is the use of a variety of raw materials through high temperature reaction and other chemical methods synthetic, its composition and characteristics can be adjusted and optimized according to the need, the chemical formula is KMg3(AlSi3O10)F2, belongs to the monoclinic crystal system, is a typical layered silicate, relatively single and pure composition. The heat resistance of natural mica powder is generally 500-600℃, and some types, such as phlogopite, can reach 800℃. The heat resistance of synthetic mica powder is more excellent, and it can withstand high temperatures above 1200℃, and the melting point or crystallization temperature is about 1375±5. The transparency of natural mica powder is relatively low, and the color is diverse, including black, yellow, white, gray, green, brown and other colors, and may vary due to different ore types and processing methods. The color of synthetic mica powder is relatively single, usually colorless transparent or white, high whiteness, good optical performance, and high transmittance from ultraviolet to infrared band.

Gneiss is another metamorphic rock type that often contains mica, alongside feldspar and quartz. Gneiss is distinguished by its banded appearance, which is a result of the segregation of minerals during the metamorphism process. Mica contributes to the overall mineral composition, adding to its structural integrity and aesthetic qualities.