Kristalopedia
Pink quartz
Pink quartz • pink quartz variety — SiO₂ Color origin: microscopic fibrous inclusion phases (similar to dumortierite) in massive pink quartz; rare pink quartz crystals, color caused by photosensitive centers...
Pink quartz
Pink quartz • pink quartz variety — SiO₂ Color origin: microscopic fibrous inclusion phases (similar to dumortierite) in massive pink quartz; rare pink quartz crystals, color caused by photosensitive centers...
Petrified wood
Petrified wood • Silicified fossil wood (permineralization + replacement) Chemistry: SiO₂ (chalcedony/agate ± opal) • Minor iron/manganese/carbon impurities Mohs ~6.5–7 (quartz level) • SG ~2.58–2.64 Textures: growth rings • rays...
Petrified wood
Petrified wood • Silicified fossil wood (permineralization + replacement) Chemistry: SiO₂ (chalcedony/agate ± opal) • Minor iron/manganese/carbon impurities Mohs ~6.5–7 (quartz level) • SG ~2.58–2.64 Textures: growth rings • rays...
Tiger eye
Tiger's eye • chatoyant quartz — pseudomorph after crocidolite (riebeckite) fibers Crystal system: trigonal (quartz) • Habit: microfibrous aggregate creating a moving "cat's eye" band Mohs: 7 • SG: ~2.64–2.71...
Tiger eye
Tiger's eye • chatoyant quartz — pseudomorph after crocidolite (riebeckite) fibers Crystal system: trigonal (quartz) • Habit: microfibrous aggregate creating a moving "cat's eye" band Mohs: 7 • SG: ~2.64–2.71...
Titnagas
Flint • dark chert variety — micro/cryptocrystalline SiO₂ Environment: nodules and layers in chalk/limestone (diagenetic silicification) Mohs scale: ~7 • SG: ~2.58–2.64 • Luster: from matte to waxy (glassy on...
Titnagas
Flint • dark chert variety — micro/cryptocrystalline SiO₂ Environment: nodules and layers in chalk/limestone (diagenetic silicification) Mohs scale: ~7 • SG: ~2.58–2.64 • Luster: from matte to waxy (glassy on...
Topaz
Topaz • aluminum fluoro-hydroxyl silicate — Al₂SiO₄(F,OH)₂ Crystal system: orthorhombic • Form: prismatic, often striated; river gravel contains worn pebbles Mohs: 8 • SG: ~3.49–3.57 • Luster: vitreous Colors: colorless,...
Topaz
Topaz • aluminum fluoro-hydroxyl silicate — Al₂SiO₄(F,OH)₂ Crystal system: orthorhombic • Form: prismatic, often striated; river gravel contains worn pebbles Mohs: 8 • SG: ~3.49–3.57 • Luster: vitreous Colors: colorless,...
Tourmalines
Tourmalines • a complex boron-containing cyclosilicate — general formula: X Y₃ Z₆ (T₆O₁₈)(BO₃)₃ V₃ W Crystal system: trigonal • Habit: long striated prisms (triangular cross-section), radial and massive aggregates Mohs:...
Tourmalines
Tourmalines • a complex boron-containing cyclosilicate — general formula: X Y₃ Z₆ (T₆O₁₈)(BO₃)₃ V₃ W Crystal system: trigonal • Habit: long striated prisms (triangular cross-section), radial and massive aggregates Mohs:...