Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Chert / Jasper
Silicon Dioxide (SiO₂)
Chert (Red/Pink Jasper subtype)
Silicon Dioxide (SiO2)
Chert (and Jasper pebble)
Microcrystalline Silica (SiO2)
Chert (Nodule)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Limestone (Brecciated/Recrystallized)
Calcium Carbonate (CaCO3)
Banded Gneiss
Gneiss (pronounced "nice")
Tiger's Eye (Polished Point/Tower)
SiO2 (Silicon Dioxide) with included crocidolite fibers
Agate / Banded Chalcedony
Agate (Silicon Dioxide / SiO2)
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)
Schist
Schist (various mineral compositions)
Howlite (White Buffalo Turquoise)
Howlite (Calcium Borosilicate Hydroxide), Ca2B5SiO9(OH)5
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Blue Sapphire
Corundum (Al2O3 - Aluminum Oxide)
Fluorite
Calcium Fluoride (CaF2)
Green Kyanite
Kyanite (Al2SiO5)
Chert (specifically Flint or Jasper variant)
Chert (Siliceous rock composed of microcrystalline Quartz, SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2)
Carnelian Agate
Chalcedony (SiO2) with iron oxide inclusions
Honey Calcite
Calcium Carbonate (CaCO3)
Milky Quartz in Matrix
Silicon Dioxide (SiO2)
Optical Calcite
Calcite (Calcium Carbonate, CaCO3)
Citrine
SiO2 (Silicon Dioxide)
Pyrite
Iron Sulfide (FeS2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Quartzite Pebble
Metamorphic Quartz (SiO2)
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2) with various iron-oxide inclusions
Pink Sapphire
Corundum (Al2O3 with trace Chromium and Iron)
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Opalite
Man-made opalescent glass (SiO2 + metal oxides)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide impurities
Rhodonite
Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3
Sandstone (Greywacke)
Arenite / Wacke (Mainly SiO2 with various lithic fragments)
Tiger's Eye (variations include Blue or Hawk's Eye)
Silicon Dioxide with Crocidolite inclusions (SiO2)
Amethyst
Quartz (SiO2) with trace iron impurities
Lapis Lazuli
Complex metamorphic rock consisting mainly of Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, Calcite, and Pyrite
Shale with Plant Fossils / Carbonaceous Shale
Laminated Mudrock (Siliciclastic)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Carnelian
Carnelian (SiO2 - Silicon Dioxide with Iron Oxide impurities)
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Pyrite
Iron Sulfide (FeS2)