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Distribution of world sillimanite resources. Sillimanite, kyanite, and andalusite (collectively referred to as the \"three stones\") are anhydrous silicate minerals that exist in three homopolymorphic variants; their chemical composition is Al2O3.SiO2, making them high-quality natural refractory materials with high aluminum content. The world’s proven reserves of sillimanite amount to approximately 1 million tons, and the main deposits that are currently mined on an industrial scale are located in India, the United States, Australia, and Africa. Of these, South Africa accounts for 53%, India for 35%, and the United States for 8%. The main producers of sillimanite are South Africa, India, and the United States. Silicate mine deposits in South Africa are concentrated in Pella, Swartkoppies, and Pofadder in the northwestern Namaguland region ； Its mineral composition is: 53% sillimanite, 41% corundum, 2.77% ilmenite, 1.19% rutile. India has huge sillimanite deposits (containing 85% sillimanite). In addition to sillimanite, this deposit also contains corundum, which appears in lenticular and nest-like forms within the crystalline schist. The sillimanite in India is mined by the Assam Sillimanite Company from deposits located in the Khasi Hills of Meghalaya State. The main component of this deposit is massive sillimanite, accompanied by a small amount of corundum, and contains trace amounts of impurities such as rutile and biotite. Chemical composition of Assam sillimanite: Al2O3 61%～63%, SiO2 35%～37%, Fe2O3 1.2～1.8%, TiO2 <0.2%, MgO <0.2%; refractoriness >1810°C, specific gravity 3.15. In addition, mining also takes place on the coasts of Madhya Pradesh, Tamil Nadu, and Kerala. 40% of the total output is exported. Due to the extremely homogeneous and dense structure of sillimanite ores in India and South Africa (porosity of 0–0.4%), some variants also contain varying amounts of corundum. Moreover, these ores are large in size and high in purity, allowing them to be cut directly into sillimanite products for use in furnaces after extraction. Especially used in the melt pool for melting flat glass, its resistance to glass erosion can match or exceed that of cast mullite-alumina refractory materials, and it also possesses good thermal shock stability. At the same time, since the “melting” of this material is also extremely uniform, it does not cause any impurities in the glass. Small pieces of ore and cut-offs are processed into raw materials for use. The United States also has promising sillimanite deposits, located in North Carolina, South Carolina, and Georgia. The sillimanite content in the ore of the deposit varies within the range of 10% to 35%. The main sillimanite deposits in the Soviet Union are the Kito and Chakhta deposits; the ore in these deposits is schist, with a sillimanite content ranging from 16% to 41%. The price of sillimanite concentrate in the world market is also relatively high. Factors affecting this price include not only the grade and particle size of the concentrate itself, but also the economic conditions of various countries, as well as maritime transportation and import/export tax policies.