struviittina

Struviittina is a hydrated magnesium ammonium phosphate mineral commonly found in the struvite group. Its chemical formula is NH4MgPO4·6H2O, and it crystallizes in the hexagonal crystal system, forming prismatic or fibrous crystals. The mineral typically has a white to colorless appearance, a Mohs hardness of 1–2, and a specific gravity around 1.69. Under a polarizing microscope, struviittina displays characteristic birefringence and a pleochroic effect when rotated.

This mineral occurs in sedimentary settings where ammonium and phosphate concentrations are high, such as in the sedimentary basins of the Baltic Sea and along the shores of the Gulf of Mexico. It is also frequently encountered as a secondary mineral in sewage sludge and wastewater treatment facilities, where it precipitates during the removal of nitrogen and phosphate. In such contexts, struviittina is often referred to simply as "struvite."

Industrial and environmental applications of struviittina include use as a slow‑release fertilizer in agriculture due to its high magnesium and nitrogen content. It is also employed as an odor control agent in livestock and waste management systems, where its precipitation with ammonium reduces the emission of ammonia. Because of its insolubility, struviittina can be used to treat wastewater streams, capturing excess phosphate and preventing eutrophication of receiving water bodies.

While primarily known for its practical uses, struviittina also holds scientific interest. Its precipitation kinetics and stability under varying pH and temperature conditions provide insights into phosphate cycling in natural and engineered environments. Research into struviittina formation aids in the development of more efficient nutrient recovery technologies and informs the assessment of its environmental impact.