GEFFROYITE Meaning and
Definition
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Geffroyite is a rare mineral belonging to the group of complex phosphates, specifically the lazulite group. It was discovered by French geologist Alfred Lacroix in the late 19th century and named after French mineralogist Maurice Geffroy. Geffroyite is known for its distinct crystal structure and beautiful blue to greenish-blue color.
This mineral is typically found in phosphate-rich pegmatite veins, in association with other rare minerals like berlinite and gormanite. Geffroyite is composed of aluminum, iron, and magnesium, combined with phosphate ions. Its chemical formula is usually represented as (Fe2+,Mg,Al)2Al4(PO4)4(OH)4•19H2O.
Geffroyite crystals often occur as prismatic or tabular forms, with a vitreous to pearly luster. It can be translucent to transparent, and its color may vary slightly due to impurities or variations in chemical composition.
Due to its rarity and distinctive appearance, geffroyite is highly sought after by mineral collectors. Its color and crystal habit make it a visually appealing specimen that can be displayed or used for aesthetic purposes. Its value is also enhanced by its scarcity.
Geffroyite is considered a secondary mineral, formed as a result of hydrothermal alterations of primary minerals. It serves as an indicator of specific geological environments and can be used in mineralogical studies to understand the geological processes involved in its formation.
