Properties of calcium carbonate and calcite

Calcium carbonate and calcite are two closely related terms, as calcite is the natural mineral form of calcium carbonate. Therefore, the physical and chemical properties of both are quite similar.

Physical properties:

• Color: It is usually colorless or white, but can be colored in different colors such as yellow, red, orange, blue, green, brown, or gray, depending on the impurities present.
• Hardness: It has a Mohs hardness of about 3, making it a medium-hard material.
• Density: Its density is about 2.71 g/cm³.
• Crystalline form: It takes different crystalline forms, including cubic and hexagonal.
• Transparency: It can be transparent, translucent or opaque.
• Refraction: It has double refraction, which means it breaks light into two separate rays.

Chemical properties:

• Chemical formula: CaCO₃
• Solubility: Practically insoluble in pure water, but dissolves in acids to form calcium salt and carbon dioxide gas.
• Reaction with acids: Reacts actively with acids, forming calcium salt and carbon dioxide gas.
• Heating: When heated to a high temperature, it decomposes into calcium oxide and carbon dioxide gas.

Formation of Kaolin

Kaolin is formed through the weathering of feldspar-rich rocks, such as granite and pegmatite. Over time, the feldspar breaks down into kaolin and other minerals. Kaolin deposits are found in many parts of the world, including China, Brazil, the United States, and Germany.

Uses of Feldspar

Feldspar has many important uses, including:

• Ceramics: Feldspar is a key ingredient in many types of ceramics, including porcelain, stoneware, and tile. It helps to improve the strength, durability, and whiteness of ceramics.
• Glass: Feldspar is used in the production of glass to improve its clarity and strength.
• Enamels: Feldspar is used in the production of enamels, which are used to coat metal surfaces.
• Fertilizers: Feldspar is a source of potassium, which is an essential nutrient for plants. It is used in fertilizers to improve crop yields.
• Abrasives: Feldspar is used in the production of abrasives, such as sandpaper and grinding wheels.
• Gemstones: Some types of feldspar, such as moonstone and labradorite, are used as gemstones.

• Construction: Marble is used for covering floors and walls, making furniture, decorating building facades, and building columns and statues.
• Sculpture: Marble is an ideal material for sculpture, as it can be carved into intricate and precise shapes.
• Handicrafts: Marble is used in the manufacture of many handicraft products such as decorative utensils and jewelry.
• Decoration: Marble adds a touch of luxury and elegance to any place, whether it is a home, office or hotel.