wollastonitt

Wollastonite is a naturally occurring calcium silicate mineral with the chemical formula CaSiO3. It crystallizes in the triclinic system, often appearing as prismatic or acicular (needle-like) crystals. Its color can range from white to gray or yellowish, and it typically has a vitreous to pearly luster. Wollastonite is relatively soft, with a Mohs hardness of 4.5 to 5, and a density of around 2.8 to 3.1 g/cm³. It is found in metamorphic rocks, particularly those formed by the contact metamorphism of limestone or dolomite with silica-rich magmas. Significant deposits are located worldwide, including in China, India, the United States, Mexico, and Finland.

The primary industrial use of wollastonite is as a functional filler and extender in various materials. Its acicular structure provides reinforcement, improving mechanical strength, dimensional stability, and abrasion resistance in plastics, paints, coatings, and ceramics. In the ceramics industry, it acts as a fluxing agent and reduces firing shrinkage and cracking, contributing to a smoother, stronger final product. Wollastonite is also employed in metallurgy as a deoxidizer and in construction materials like cement and asphalt. Due to its low moisture absorption and good electrical insulating properties, it finds applications in electrical components. Its non-toxic nature and environmental friendliness contribute to its growing popularity as a substitute for other mineral fillers.

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