Collection: Magnesite

Magnesite is a mineral composed primarily of magnesium carbonate (MgCO₃). It is an important source of magnesium , a chemical element used in many industrial and medical fields.

🔹 Main Features

• Chemical formula : MgCO₃

• Crystal system : Trigonal (often in rhombohedral crystals, but also massive or fibrous)

• Color : White, gray, yellowish, sometimes tinged with brown or greenish

• Hardness (Mohs scale) : 3.5 to 4.5

• Density : Approx. 3.0 g/cm³

• Luster : Vitreous to dull

• Transparency : Translucent to opaque

🔹 Training and deposits

Magnesite is formed primarily by hydrothermal alteration or metasomatism of magnesium-rich rocks, such as peridotites or serpentinites . It can also precipitate directly from waters rich in Mg²⁺ and CO₃²⁻, in certain sedimentary environments.

Notable deposits :

• China (world's largest producer)

• Türkiye

• Brazil

• Slovakia

• Austria

• Greece

🔹 Uses

• Source of metallic magnesium (by reduction)

• Refractories : used in materials resistant to very high temperatures (for example, in metallurgical furnaces)

• Chemical industry : production of magnesium compounds (such as magnesium oxide, MgO)

• Health : sometimes used as a laxative or antacid (purified forms)

• Ornamentation : some magnesites, naturally or artificially colored, are used as semi-precious stones (often sold as imitations of turquoise)

🔹 Environmental and geological aspects

• Magnesite has been studied for CO₂ storage because it can form from carbon dioxide and magnesium-rich minerals—a process potentially useful for carbon sequestration .

• It is a geological indicator of certain ultramafic environments.