Banded Iron Formation
Banded Iron Formation (BIF)
Category
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Banded Iron Formation
Banded Iron Formation (BIF)
Emerald and Diamond (Jewelry Setting)
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities) and Carbon (C)
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
Agate (specifically Waterline or Onyx-type Agate)
Silicon Dioxide (SiO2) - variety Chalcedony
Jade (Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Anthracite Coal
Anthracite
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Epidote
Epidote Group (e.g., Clinozoisite, Epidote, Piemontite), Epidote formula: Ca2(Al,Fe)3(SiO4)3(OH)
Ferromanganese Nodule
Polymetallic Nodule (composed primarily of MnO2 and Fe2O3)
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
Lepidolite
K(Li,Al)3(Si,Al)4O10(F,OH)2
Limestone
CaCO3 (principally Calcite)
Diopside (likely Chromian Diopside)
Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.
Anthracite Coal
Anthracite
Peach Moonstone
Potassium Aluminum Silicate (KAlSi3O8); variety of Orthoclase Feldspar
Quartzite
Quartzite
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Carnelian (Orange Agate)
Silicon Dioxide (SiO2)
Calcite
Calcite (CaCO3)
Quartzite
Quartzite (primarily SiO2)
Rough Sapphire (Corundum)
Corundum (Al2O3)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Anthracite Coal
Anthracite (Carbon-rich Sedimentary Rock)
Fossil Coral
Fossilized Scleractinia or Tabulata (various genera/species)
Quartz (Float/Abraded)
Quartz (SiO₂)
Fluorite Bracelet (light green beads) and possibly Lavender Jadeite (purple bead)
Fluorite: CaF₂ (Calcium Fluoride); Jadeite: NaAlSi₂O₆ (Sodium Aluminum Silicate)
Lapis Lazuli
Lapis Lazuli (a rock type, not a single mineral; main component is Lazurite (Na,Ca)8[(S,Cl,SO4,OH)2|(Al6Si6O24)])
Red Garnet
Garnet Group (e.g., Pyrope, Almandine, Spessartine, Grossular, Andradite, Uvarovite)
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite, Sodalite, Calcite, and Pyrite)
Sunstone
Plagioclase feldspar (with Copper or Hematite inclusions)
Yellow Chalcedony
Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Amethyst
Quartz (SiO2) variety
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
River Rock / Stream Pebble
Fluvial Clast / Rounded Sedimentary Particle
Garnet (likely Almandine, Pyrope, or a blend)
Garnet group minerals: X3Y2(SiO4)3, where X and Y represent various metal ions (e.g., Almandine: Fe3Al2(SiO4)3, Pyrope: Mg3Al2(SiO4)3)
Quartz (likely)
Quartz (SiO2 - Silicon Dioxide)
Sandstone
Arenite (primarily SiO2)
Rutilated Quartz
Silicon Dioxide (SiO2) with Titanium Dioxide (TiO2) inclusions