Crystals
Lizardite
Lizardite • Serpentine group (phyllosilicate) Formula: Mg3Si2O5(OH)4 (± minor Fe, Ni, Al) Crystal system: Trigonal polytype (1T/2H) • Platy habit Mohs ~2.5–3.5 • SG ~2.55–2.62 Luster: Greasy–waxy • Cleavage: Perfect...
Lizardite
Lizardite • Serpentine group (phyllosilicate) Formula: Mg3Si2O5(OH)4 (± minor Fe, Ni, Al) Crystal system: Trigonal polytype (1T/2H) • Platy habit Mohs ~2.5–3.5 • SG ~2.55–2.62 Luster: Greasy–waxy • Cleavage: Perfect...
Magnetite
Magnetite • Fe3O4 • Inverse spinel Crystal System: Isometric (cubic) Mohs ~5.5–6.5 • SG ~5.1–5.2 Streak: Black • Luster: Metallic–submetallic Magnetism: Strongly magnetic (ferrimagnetic) Magnetite — The Mineral that Brings...
Magnetite
Magnetite • Fe3O4 • Inverse spinel Crystal System: Isometric (cubic) Mohs ~5.5–6.5 • SG ~5.1–5.2 Streak: Black • Luster: Metallic–submetallic Magnetism: Strongly magnetic (ferrimagnetic) Magnetite — The Mineral that Brings...
Muscovite
Muscovite • KAl₂(AlSi₃O₁₀)(OH)₂ — potassium “white mica” (phyllosilicate) Crystal system: Monoclinic • Habit: books, sheets, flakes, rosettes Mohs: ~2–2.5 • SG: ~2.76–3.0 • Cleavage: perfect {001} (peels into elastic sheets)...
Muscovite
Muscovite • KAl₂(AlSi₃O₁₀)(OH)₂ — potassium “white mica” (phyllosilicate) Crystal system: Monoclinic • Habit: books, sheets, flakes, rosettes Mohs: ~2–2.5 • SG: ~2.76–3.0 • Cleavage: perfect {001} (peels into elastic sheets)...
Vesuvianite
Vesuvianite (a.k.a. idocrase) • complex calcium–aluminum sorosilicate Approx. formula: Ca₁₀(Mg,Fe)₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)₄ (variable) Crystal system: Tetragonal • Habit: prismatic, square cross‑sections, granular/massive Mohs: ~6–6.5 (up to ~7) • SG: ~3.3–3.45 • Luster:...
Vesuvianite
Vesuvianite (a.k.a. idocrase) • complex calcium–aluminum sorosilicate Approx. formula: Ca₁₀(Mg,Fe)₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)₄ (variable) Crystal system: Tetragonal • Habit: prismatic, square cross‑sections, granular/massive Mohs: ~6–6.5 (up to ~7) • SG: ~3.3–3.45 • Luster:...
Vanadinite
Vanadinite • lead chlorovanadate — Pb₅(VO₄)₃Cl (apatite‑group) Crystal system: Hexagonal • Habit: short hexagonal prisms, often barrel‑shaped, rosettes, crusts Color: cherry‑red → orange‑red → brownish; transparency: translucent to opaque Mohs:...
Vanadinite
Vanadinite • lead chlorovanadate — Pb₅(VO₄)₃Cl (apatite‑group) Crystal system: Hexagonal • Habit: short hexagonal prisms, often barrel‑shaped, rosettes, crusts Color: cherry‑red → orange‑red → brownish; transparency: translucent to opaque Mohs:...
Rhyolite
Rhyolite • felsic volcanic rock — extrusive equivalent of granite Texture: aphanitic to porphyritic (fine groundmass with phenocrysts) • Features: flow banding, spherulites, lithophysae Phenocrysts: quartz, sanidine (K‑feldspar), plagioclase •...
Rhyolite
Rhyolite • felsic volcanic rock — extrusive equivalent of granite Texture: aphanitic to porphyritic (fine groundmass with phenocrysts) • Features: flow banding, spherulites, lithophysae Phenocrysts: quartz, sanidine (K‑feldspar), plagioclase •...