Crystals
Lepidolite
Lithium-rich mica series K(Li,Al)3(Si,Al)4O10(F,OH)2 Trioctahedral sheet silicate Typically monoclinic polytypes Perfect basal cleavage Mohs approximately 2.5–4 Lilac, lavender, rose, violet-gray, and silver Late-stage LCT pegmatites Historic source material in rubidium...
Lepidolite
Lithium-rich mica series K(Li,Al)3(Si,Al)4O10(F,OH)2 Trioctahedral sheet silicate Typically monoclinic polytypes Perfect basal cleavage Mohs approximately 2.5–4 Lilac, lavender, rose, violet-gray, and silver Late-stage LCT pegmatites Historic source material in rubidium...
Magnesite
Magnesium carbonate MgCO3 Calcite-group mineral Trigonal crystal system Mohs approximately 3.5–4.5 Perfect rhombohedral cleavage Carbonation of magnesium-rich rock Naturally pale, often dyed Magnesite: The White Carbonate Behind Many Colors Magnesite...
Magnesite
Magnesium carbonate MgCO3 Calcite-group mineral Trigonal crystal system Mohs approximately 3.5–4.5 Perfect rhombohedral cleavage Carbonation of magnesium-rich rock Naturally pale, often dyed Magnesite: The White Carbonate Behind Many Colors Magnesite...
Lizardite
Serpentine-group phyllosilicate Mg3Si2O5(OH)4 Platy layered structure Mohs approximately 2.5–3.5 Waxy to greasy luster Forms through serpentinization Commonly associated with magnetite Named for the Lizard Peninsula Lizardite: The Platy Serpentine Mineral...
Lizardite
Serpentine-group phyllosilicate Mg3Si2O5(OH)4 Platy layered structure Mohs approximately 2.5–3.5 Waxy to greasy luster Forms through serpentinization Commonly associated with magnetite Named for the Lizard Peninsula Lizardite: The Platy Serpentine Mineral...
Magnetite
Iron oxide mineral Fe3O4 Inverse spinel structure Isometric crystal system Mohs approximately 5.5–6.5 Black streak and metallic luster Strong ferrimagnetism Curie temperature near 580°C Major iron ore and geological recorder...
Magnetite
Iron oxide mineral Fe3O4 Inverse spinel structure Isometric crystal system Mohs approximately 5.5–6.5 Black streak and metallic luster Strong ferrimagnetism Curie temperature near 580°C Major iron ore and geological recorder...
Muscovite
Dioctahedral mica KAl2(AlSi3O10)(OH,F)2 Monoclinic, commonly 2M1 Perfect basal cleavage Mohs about 2–2.5 along the sheets Elastic transparent leaves Pearly to vitreous luster Fuchsite and fine white-mica forms Muscovite: The Shimmering...
Muscovite
Dioctahedral mica KAl2(AlSi3O10)(OH,F)2 Monoclinic, commonly 2M1 Perfect basal cleavage Mohs about 2–2.5 along the sheets Elastic transparent leaves Pearly to vitreous luster Fuchsite and fine white-mica forms Muscovite: The Shimmering...
Vesuvianite
Vesuvianite • traditional synonym: idocrase Representative formula: Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4 Complex calcium–aluminum sorosilicate Tetragonal • square-section prisms and stepped pyramids Mohs about 6–7 • specific gravity about 3.32–3.45 Vitreous to resinous •...
Vesuvianite
Vesuvianite • traditional synonym: idocrase Representative formula: Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4 Complex calcium–aluminum sorosilicate Tetragonal • square-section prisms and stepped pyramids Mohs about 6–7 • specific gravity about 3.32–3.45 Vitreous to resinous •...