1301. Formula of hydroxyapatite crystal is____________? September 27, 2025 by Admin A. Ca3 (Po4)2 CaCo3 B. 3Ca (Po4)2 Ca(OH)2 C. CaPo4 Ca(OH)2 D. None of the above ✅ The correct answer is option B. 3Ca (Po4)2 Ca(OH)2.