Sapphire
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium,... Wikipedia
- Category: Oxide mineral
- Formula, (repeating unit): Aluminium oxide, Al 2O 3
- Crystal system: Trigonal
- Crystal class: Hexagonal scalenohedral (3m), H-M symbol: (32/m)
- Space group: R 3c
- Color: Typically blue, but varies
- Crystal habit: As crystals, massive and granular
- Twinning: Both growth twins (in various orientations) and polysynthetic glide twinning on the rhombohedron [10 11 | cleavage = Poor | fracture = Conchoidal, splintery | mohs = 9.0 | luster = Vitreous | refractive = n ω = 1.768–1.772, n ε = 1.760–1.763, birefringence 0.008 | opticalprop = Abbe number 72.2 | pleochroism = Strong | streak = Colorless | gravity = 3.98–4.06 | density = | melt = 2,030–2,050 °C | fusibility = Infusible | diagnostic = | solubility = Insoluble | diaphaneity = Transparent to nearly opaque | other = Coefficient of thermal expansion (5.0–6.6) × 10 −6 /K, relative permittivity at 20 °C, ε = 8.9–11.1 (anisotropic) | label15 = Cleavage | data15 = | label16 = Fracture | data16 = | label17 = Tenacity | data17 = | label18 = Mohs scale hardness | data18 = | label19 = Luster | data19 = | label20 = Streak | data20 = | label21 = Diaphaneity | data21 = | label22 = Specific gravity | data22 = | label23 = Density | data23 = | label24 = Polish luster | data24 = | label25 = Optical properties | data25 = | label26 = Refractive index | data26 = | label27 = Birefringence | data27 = | label28 = Pleochroism | data28 = | label29 = 2V angle | data29 = | label30 = Dispersion | data30 = | label31 = Extinction | data31 = | label32 = Length fast/slow | data32 = | label33 = Ultraviolet fluorescence | data33 = | label34 = Absorption spectra | data34 = | label35 = Melting point | data35 = | label36 = Fusibility | data36 = | label37 = Diagnostic features | data37 = | label38 = Solubility | data38 = | label39 = Common impurities | data39 = | label40 = Alters to | data40 = | label41 = Other characteristics | data41 = | label42 = | data42 = | label43 = References | data43 = | header44 = | label45 = | data45 = | label46 = | data46 = | label47 = | data47 = | label48 = | data48 = | label49 = | data49 = | label50 = | data50 =
- Data source: DuckDuckGo