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.[1] |
| Perawakan | Tabular, prismatic crystals, massive, compact or granular |
| Sistem kristal | Hexagonal dipyramidal (6/m)[2] |
| Belahan | [0001] indistinct, [1010] indistinct[2] |
| Pecahan | Conchoidal to uneven[1] |
| Kekerasan (Skala Mohs) | 5[1] (defining mineral) |
| Kilap | Vitreous[1] to subresinous |
| Gores | White |
| Diafaneitas | Transparent to translucent[2] |
| Berat jenis | 3.16–3.22[2] |
| Kilapan poles | Vitreous[1] |
| Sifat optik | Double refractive, uniaxial negative[1] |
| Indeks bias | 1.634–1.638 (+0.012, −0.006)[1] |
| Bias ganda | 0.002–0.008[1] |
| Pleokroisme | Blue stones – strong, blue and yellow to colorless. Other colors are weak to very weak.[1] |
| Dispersi | 0.013[1] |
| 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.[1] |