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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
KategoriPhosphate mineral
Rumus kimiaCa5(PO4)3(F,Cl,OH)
Klasifikasi Strunz08.BN.05
Identifikasi
WarnaTransparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown.[1]
PerawakanTabular, prismatic crystals, massive, compact or granular
Sistem kristalHexagonal dipyramidal (6/m)[2]
Belahan[0001] indistinct, [1010] indistinct[2]
PecahanConchoidal to uneven[1]
Kekerasan (Skala Mohs)5[1] (defining mineral)
KilapVitreous[1] to subresinous
GoresWhite
DiafaneitasTransparent to translucent[2]
Berat jenis3.16–3.22[2]
Kilapan polesVitreous[1]
Sifat optikDouble refractive, uniaxial negative[1]
Indeks bias1.634–1.638 (+0.012, −0.006)[1]
Bias ganda0.002–0.008[1]
PleokroismeBlue stones – strong, blue and yellow to colorless. Other colors are weak to very weak.[1]
Dispersi0.013[1]
Fluoresens ultravioletYellow 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.[1]

ReferensiSunting

  1. ^ a b c d e f g h i j k Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
  2. ^ a b c d Apatite. Webmineral