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Gemstone Encyclopedia
What Traces of Iron and Titanium Really Do Insi...
Blue sapphire color comes mainly from iron-titanium intervalence charge transfer in corundum, not from iron alone. Learn how trace elements, oxidation states, and treatment affect sapphire.
What Traces of Iron and Titanium Really Do Insi...
Blue sapphire color comes mainly from iron-titanium intervalence charge transfer in corundum, not from iron alone. Learn how trace elements, oxidation states, and treatment affect sapphire.
Selenite, Gypsum, and the Hidden Role of Crysta...
Why cutting orientation matters in selenite: gypsum's monoclinic structure, perfect cleavage, and high birefringence create direction-dependent optical and mechanical effects.
Selenite, Gypsum, and the Hidden Role of Crysta...
Why cutting orientation matters in selenite: gypsum's monoclinic structure, perfect cleavage, and high birefringence create direction-dependent optical and mechanical effects.
Brazilian Emerald: Reading Identity Through Ref...
Brazilian emerald is a trade label, not a mineral species. See how beryl's refractive index and birefringence identify emerald, and what inclusions can reveal about origin.
Brazilian Emerald: Reading Identity Through Ref...
Brazilian emerald is a trade label, not a mineral species. See how beryl's refractive index and birefringence identify emerald, and what inclusions can reveal about origin.
Sphene, Dispersion, and the Limits of the "Fire...
Sphene (titanite) has greater dispersion than diamond, but its body color, high birefringence, and strong pleochroism limit visible fire. A gemological explanation of this optical exception.
Sphene, Dispersion, and the Limits of the "Fire...
Sphene (titanite) has greater dispersion than diamond, but its body color, high birefringence, and strong pleochroism limit visible fire. A gemological explanation of this optical exception.
Why Peridot Rarely Glows: Fluorescence, Phospho...
Why peridot rarely fluoresces or phosphoresces, how iron quenches luminescence, and what lily-pad fractures, chromite crystals, and other inclusions reveal about peridot identity.
Why Peridot Rarely Glows: Fluorescence, Phospho...
Why peridot rarely fluoresces or phosphoresces, how iron quenches luminescence, and what lily-pad fractures, chromite crystals, and other inclusions reveal about peridot identity.
Red Jasper, Microcrystalline Quartz, and the Li...
Red jasper is a microcrystalline quartz aggregate, so its toughness depends on fracture and aggregate structure rather than Mohs hardness alone. Learn how it differs from macrocrystalline quartz.
Red Jasper, Microcrystalline Quartz, and the Li...
Red jasper is a microcrystalline quartz aggregate, so its toughness depends on fracture and aggregate structure rather than Mohs hardness alone. Learn how it differs from macrocrystalline quartz.