#silicate

• Adularia — A structural variety of orthoclase (potassium feldspar) presenting as transparent to translucent, colorless or whitish crystals, characterized by a specific silvery or opalescent schiller known as adularism. Named after the Adula Alps in Switzerland, where it was historically found within hydrothermal veins of metamorphic rocks. Due to its unique optical properties, fine specimens are cut as moonstones for gemology, while bulk materials are applied in high-grade ceramics and glass manufacturing.
• Aerosiderolite — A rare type of mixed meteorite, macro-structurally composed of a relatively equal mixture of silicate mass (olivine-type minerals or pyroxenes) and a metallic iron-nickel alloy. In a historical or contextual sense, the term designates celestial bodies that enter Earth's atmosphere, whose fragments collected on the ground provide precious geochemical data about early planetary core compositions.
• Agatine — Pertaining to agate, relating to agate, or having the appearance, texture, or structural properties of this variety of chalcedony. In a technical or mineralogical sense, it describes materials, silicated rocks, or siliceous layers that exhibit parallel bands of different colors or a finely zoned texture characteristic of semi-precious stones within the silicate class.
• Akermanite — A mineral belonging to the melilite group, consisting of a complex calcium and magnesium silicate with the chemical formula Ca2MgSi2O7; it crystallizes in the tetragonal system and frequently occurs in silica-poor effusive igneous rocks, in contact-metamorphosed limestones, or as a major structural component in industrial metallurgical slags. This high-temperature mineral forms a continuous isomorphous series with gehlenite, being utilized in petrological studies to determine the thermodynamic conditions of magma solidification.
• Aldur — A scientific term or rare variant designating a specific type of granular mineral aggregate or a microcrystalline structural variety found in ancient igneous rocks. In a broader sense, the word is analyzed in comparative petrology studies to describe silicate formations resistant to thermal erosion, which develop under extreme pressure conditions in the Earth's crust.
• Alfel — A rare mineralogical term used to describe a specific variety of feldspar or a microcrystalline structure associated with native silicates. In older geological papers, the word referred to structural compounds of magmatic rocks, acting as a technical neologism systematically tracking granular textures.
• Alite — The main mineralogical and crystallo-chemical constituent of Portland cement clinker, consisting primarily of tricalcium silicate impure with small amounts of aluminum, iron, and magnesium oxides. Alite is responsible for setting and early strength development.
• Almandine — A silicate mineral representing the most widespread and common species of the garnet group, featuring a characteristic deep red, purplish-red, reddish-brown, or black color, containing iron and aluminum. It crystallizes in the cubic system, has a vitreous luster, and high hardness (7-7.5 on the Mohs scale), with its transparent varieties utilized since antiquity as semi-precious gemstones in jewelry and opaque ones as industrial abrasives.
• Allophane — An amorphous or poorly crystalline hydrated aluminum silicate mineral, often associated with the weathering of volcanic rocks and ash deposits in humid environments. This structural compound exhibits a variable chemical composition and a gelatinous or vitreous texture, holding significant importance in soil science due to its high cation exchange capacity and phosphate-fixing ability in andosols.
• Allophane — Minerals from the hydrated aluminum silicate class, amorphous or poorly crystalline, which form structurally through the weathering of volcanic rocks (ash and basalt) under the action of meteoric waters; they are characterized by high porosity and a large ion-exchange capacity, being specific to andosol-type soils.
• Alloshite — A rare mineral or complex silicate discovered within certain metamorphic rocks or hydrothermal deposits, structurally characterized by an atypical crystalline lattice and associations with micro-mineral aggregates of foreign (allogenous) origin. This geological compound is analyzed via X-ray diffraction to establish the specific pressure and temperature conditions in the earth's crust at the moment of its crystallization.
• Aluminosilicate — A complex mineral within the silicate class (representing a large portion of the Earth's crust, such as feldspars, zeolites, and micas) in whose crystalline frameworks part of the silicon atoms are replaced by aluminum atoms bound to oxygen.
• Alumosilicate — A terminological or spelling variant (influenced by German and Russian nomenclatures) for 'aluminosilicat' (aluminosilicate); a complex mineral within the silicate class in whose crystalline frameworks part of the silicon atoms are replaced by aluminum atoms.
• Amphibole — A generic name for an extensive group of inosilicate minerals with a monoclinic or orthorhombic crystalline structure, composed of double chains of silicon dioxide tetrahedra. This structural group, which includes hornblende, actinolite, and tremolite, typically contains iron, magnesium, calcium, and sodium ions, being an essential constituent of many dark-colored igneous and metamorphic rocks.
• Amiantus — A variety of asbestos with long, flexible, and silky fibers of a whitish-green color, resistant to high temperatures and acid actions. Structurally, it is a natural calcium and magnesium silicate widely used in the past for manufacturing fireproof fabrics, thermal insulators, and building materials, but modernly restricted due to its severe pulmonary toxicity.
• Amiantus — A rare feminine form or accepted regional variant for the mineral amiantus; it defines the same incombustible fibrous rock from the natural silicate class, used as an insulating raw material in traditional industrial applications.
• Anait — A rare technical term or mineralogical variant designating a crystalline compound or a natural silicate studied within specific geological structures; it can also be encountered in old chemical nomenclature as a transcription variant for certain saline or acid derivatives. As an adjective, it describes a compact material or rock formation whose physicochemical properties are linked to this structural compound.
• Analcite — An older terminological or spelling variant contextually used for the mineral analcime (analcite), a hydrated sodium and aluminum silicate from the zeolite group. Structurally characterized by white, grey, or colorless isometric (icositetrahedral) crystals, this natural compound forms through hydrothermal processes in the cavities of basaltic magmatic rocks or as an authigenic mineral in some sedimentary rocks, studied in systematic mineralogy for its ion-exchange properties.
• Analcite — A mineral belonging to the silicate class (tectosilicates subclass), structurally considered a member of the zeolite or feldspathoid group, with the chemical formula NaAlSi2O6·H2O. It occurs as regular cubic or trapezohedral (icositetrahedral) crystals, colorless, white, or pink, with a vitreous luster, frequently found in basalt geodes, alkaline igneous rocks, and some saline lacustrine sedimentary deposits.
• Andalusite — A structural mineral consisting of aluminum silicate that crystallizes in the orthorhombic system, being characteristic of metamorphic rocks formed under low pressures and medium to high temperatures. Due to its exceptional thermal resistance and high melting point, andalusite is widely used in industry as a refractory material for lining metallurgical furnaces, while its transparent and colored varieties are sometimes used as gemstones in jewelry.