#igneous rocks

• Alkalic — Containing alkali; having basic or alkaline properties; alkaline. In geology and petrography, the term describes igneous rocks or minerals rich in alkali metals (such as sodium and potassium), characterized by a specific chemical composition that influences the structure and evolution of crustal melts.
• 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.
• Allotriomorphic — Relating to minerals or crystalline components of an igneous rock: not presenting its own geometric faces or a regular native external shape, because its structural development was limited and constrained by the free spaces remaining between crystals formed earlier during magma solidification.
• Andesine — A mineral belonging to the silicate class, specifically an intermediate variety of plagioclase feldspar, structurally defined by a specific chemical ratio between albite and anorthite (between 30% and 50% anorthite). It is a common constituent of intermediate igneous rocks, such as andesites and diorites, receiving its name from the Andes Mountains, where it was initially identified and abundantly described.
• Andesine — A mineral belonging to the plagioclase feldspar group, consisting of an isomorphic mixture of albite and anorthite in determined proportions, being a natural silicate of aluminum, calcium, and sodium. It crystallizes in the triclinic system and represents an essential and diagnostic component in the structure of intermediate igneous rocks, its name being linked to its abundant occurrence in the Andes mountain range.