Kristalopedia
Sunstone
Sunstone • mineral with aventurine feldspar shimmer — usually plagioclase (oligoclase → labradorite) with metallic plates Ideal series: NaAlSi₃O₈–CaAl₂Si₂O₈ • Occasionally orthoclase (KAlSi₃O₈) Crystal system: triclinic (plagioclase) • Habit: tabular...
Sunstone
Sunstone • mineral with aventurine feldspar shimmer — usually plagioclase (oligoclase → labradorite) with metallic plates Ideal series: NaAlSi₃O₈–CaAl₂Si₂O₈ • Occasionally orthoclase (KAlSi₃O₈) Crystal system: triclinic (plagioclase) • Habit: tabular...
Lizarditas
Lizardite • serpentine group (phyllosilicate) Formula: Mg3Yes2O5(OH)4 (± a little Fe, Ni, Al) Crystal system: trigonal polymorph (1T/2H) • platy habit Mohs ~2.5–3.5 • SG ~2.55–2.62 Luster: greasy–waxy • Cleavage:...
Lizarditas
Lizardite • serpentine group (phyllosilicate) Formula: Mg3Yes2O5(OH)4 (± a little Fe, Ni, Al) Crystal system: trigonal polymorph (1T/2H) • platy habit Mohs ~2.5–3.5 • SG ~2.55–2.62 Luster: greasy–waxy • Cleavage:...
Lepidolitas
Lepidolite • lithium-rich mica (trioctahedral) Approximate formula: K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2 Crystal system: monoclinic (pseudohexagonal plates) Mohs ~2.5–3 • SG ~2.8–2.9 Cleavage: perfect on {001} (mica flakes) Palette: lilac • lavender • pink...
Lepidolitas
Lepidolite • lithium-rich mica (trioctahedral) Approximate formula: K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2 Crystal system: monoclinic (pseudohexagonal plates) Mohs ~2.5–3 • SG ~2.8–2.9 Cleavage: perfect on {001} (mica flakes) Palette: lilac • lavender • pink...
Magnesite
Magnesite • MgCO₃ — magnesium carbonate (calcite group) Crystal system: trigonal (rhombohedral) • Cleavage: perfect rhombohedral Mohs scale: ~3.5–4.5 • SG: ~3.0–3.1 • Luster: vitreous to dull (often "chalky") Behavior:...
Magnesite
Magnesite • MgCO₃ — magnesium carbonate (calcite group) Crystal system: trigonal (rhombohedral) • Cleavage: perfect rhombohedral Mohs scale: ~3.5–4.5 • SG: ~3.0–3.1 • Luster: vitreous to dull (often "chalky") Behavior:...
Emeralds
Emerald • green beryl variety — Be₃Al₂Si₆O₁₈, color caused by Cr³⁺/V³⁺ Crystal system: hexagonal • Habit: long prismatic crystals, etched crystals, massive Mohs: ~7.5–8 • SG: ~2.67–2.78 • RI (spot):...
Emeralds
Emerald • green beryl variety — Be₃Al₂Si₆O₁₈, color caused by Cr³⁺/V³⁺ Crystal system: hexagonal • Habit: long prismatic crystals, etched crystals, massive Mohs: ~7.5–8 • SG: ~2.67–2.78 • RI (spot):...
Lapis lazuli
Lapis lazuli • metamorphosed rock, rich in lazurite (sodalite group) with calcite and pyrite Color cause (in lazurite): S3− radical anions and related sulfur compounds Hardness: ~5–5.5 • SG: ~2.7–2.9...
Lapis lazuli
Lapis lazuli • metamorphosed rock, rich in lazurite (sodalite group) with calcite and pyrite Color cause (in lazurite): S3− radical anions and related sulfur compounds Hardness: ~5–5.5 • SG: ~2.7–2.9...