Apatit

Apatit adalah kelompok mineral fosfat, biasanya mengacu hidroksilapatit, fluorapatit dan klorapatit, dengan konsentrasi tinggi ion OH⁻, F⁻ dan Cl⁻, secara berurutan, dalam kristal. Rumus dari campuran dari empat endmembers paling umum ditulis sebagai Ca₁₀(PO₄)₆(OH,F,Cl)₂, dan rumus satuan kristal sel mineral individu ditulis sebagai Ca₁₀(PO₄)₆(OH)₂, Ca₁₀(PO₄)₆(F)₂ and Ca₁₀(PO₄)₆(Cl)₂.

Apatite group
Umum
Kategori	Phosphate mineral
Rumus kimia	Ca5(PO4)3(F,Cl,OH)
Klasifikasi Strunz	08.BN.05
Identifikasi
Warna	Transparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown.
Perawakan	Tabular, prismatic crystals, massive, compact or granular
Sistem kristal	Hexagonal dipyramidal (6/m)
Belahan	[0001] indistinct, [1010] indistinct
Pecahan	Conchoidal to uneven
Kekerasan (Skala Mohs)	5 (defining mineral)
Kilap	Vitreous to subresinous
Gores	White
Diafaneitas	Transparent to translucent
Berat jenis	3.16–3.22
Kilapan poles	Vitreous
Sifat optik	Double refractive, uniaxial negative
Indeks bias	1.634–1.638 (+0.012, −0.006)
Bias ganda	0.002–0.008
Pleokroisme	Blue stones – strong, blue and yellow to colorless. Other colors are weak to very weak.
Dispersi	0.013
Fluoresens ultraviolet	Yellow stones – purplish-pink, which is stronger in long wave; blue stones – blue to light-blue in both long and short wave; green stones – greenish-yellow, which is stronger in long wave; violet stones – greenish-yellow in long wave, light-purple in short wave.