What is Ludlamite?
Ludlamite is a soft hydrated iron phosphate known for vivid green crystals in phosphate-rich granite pegmatites and altered ore environments.
Mineralogy and crystal structure
Reference formula: Fe3(PO4)2·4H2O. Ludlamite is a monoclinic hydrated phosphate. Iron oxidation and substitution can influence its green colour and stability, while surface alteration may produce darker or earthy coatings; fresh crystal faces are more informative than weathered surfaces. Ludlamite is classified with phosphates and has a monoclinic crystal system. Typical hardness is 3.5–4 on the Mohs scale and specific gravity is approximately 3.1–3.2.
Colour, lustre and habit
Typical colours include green, pale green, blue-green, brown. The usual prismatic, tabular, granular habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Ludlamite forms in or is associated with granite pegmatites, phosphate-rich cavities and hydrothermal alteration zones. Important documented localities include Brazil, Bolivia, the United States, Portugal, Germany and Australia.
A green phosphate for the pegmatite collector
Ludlamite is a memorable cabinet mineral because its soft green crystals feel unusually fresh against the granitic matrix. It is especially rewarding in a phosphate suite, where colour, hydration and pegmatite chemistry can be read together.
Collecting and care
Soft and sensitive: protect from abrasion, strong light and humidity, and avoid acids or cleaning solutions.
