Hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂) is a high-value calcium phosphate used extensively in biomedical applications (bone grafts, implant coatings, dental products), specialty chromatography media, and some filtration/resin supports. Manufacture can be from synthetic chemical routes (controlled precipitation from calcium and phosphate salts), wet-chemical hydrothermal methods, or by processing bio-derived precursors (e.g., bovine or fish bone-derived HA) for certain markets.