Effect of heat treatment on the luminescence properties of natural apatite

Chemical Composition and Spectroscopic Characteristics of Alexandrite Effect Apatite from the Akzhailyau Mountains of Kazakhstan

“…Apatite is a phosphorus mineral characterized by a complex chemical composition. Its general formula is A 10 [PO 4 ] 6 Z 2 [1][2][3][4][5][6][7][8][9]. In this formula, 'A' signifies a divalent cation, primarily represented by Ca 2+ .…”

“…In this configuration, some of the Ca is substituted by elements such as Mn, Ce, Nd, La, and Sm. Additionally, portions of [PO 4 ] are replaced by [SiO 4 ], and some F ions are substituted by OH [4][5][6][7][8]. These variations manifest as different shades of apatite-blue, yellow, pink, and green-which enhance its appeal in the gemstone market [4][5][6][7][8].…”

“…Additionally, portions of [PO 4 ] are replaced by [SiO 4 ], and some F ions are substituted by OH [4][5][6][7][8]. These variations manifest as different shades of apatite-blue, yellow, pink, and green-which enhance its appeal in the gemstone market [4][5][6][7][8]. In gemological terms, the frequent isomorphic substitutions in apatite lead to diverse defects, presenting as different colors [4][5][6][7][8].…”

“…These variations manifest as different shades of apatite-blue, yellow, pink, and green-which enhance its appeal in the gemstone market [4][5][6][7][8]. In gemological terms, the frequent isomorphic substitutions in apatite lead to diverse defects, presenting as different colors [4][5][6][7][8]. Ideally, as an allochromatic gemstone, clear apatite should be colorless.…”

“…However, its proclivity for isomorphous substitutions and crystal structure changes render it multicolored. These vibrant hues can be largely attributed to Minerals 2023, 13, 1139 2 of 12 the presence of rare-earth elements (REE), transition metal ions (primarily Mn and Fe), and, more broadly, color centers [4][5][6][7][8].…”