Ferruginous Chert
Silicon dioxide with iron oxide impurities (SiO2 + Fe2O3)
Category
Browse sedimentary (alluvial deposit) specimens identified by the Rock Identifier community.
Ferruginous Chert
Silicon dioxide with iron oxide impurities (SiO2 + Fe2O3)
Limonite (Iron Ore)
Limonite (Iron oxide-hydroxide mixture, FeO(OH)·nH2O)
Shale
Shale (Lutite)
Optical Calcite (Iceland Spar)
Calcium Carbonate (CaCO3)
Silty Shale
Silty Shale (Fissile Sedimentary Rock)
Shale (Ferruginous)
Laminated Mudrock (Siliciclastic Sedimentary Rock)
Banded Slate (Lithified Mudstone)
Low-grade Metamorphosed Mudstone / Slate
Amber (Copal)
Fossilized Tree Resin (C10H16O)
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
Septarian Nodule
Septarian Concretion (Complex of Calcite, Aragonite, and Limestone/Mudstone)
Jasper (brecciated or orbicular variety)
Silicon dioxide (SiO2) with iron oxide inclusions
Gold Nugget
Native Gold (Au)
Yellow Jasper
Jasper (Silica-rich Microcrystalline Quartz, SiO2)
Red Jasper
Jasper (Silicon Dioxide, SiO2)
Siltstone with flute casts or scratch marks
Clastic Sedimentary Rock (Siltstone/Fine-grained Sandstone)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
Red Jasper
Jasper (SiO2) with Hematite (Fe2O3) inclusions
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Galena
Lead(II) sulfide (PbS)
Limestone with Chert or Siltstone bands
Sedimentary carbonate rock (CaCO3) often with siliceous impurities
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
Orange Quartz (or Tumbled Carnelian)
Silicon Dioxide (SiO2) with iron oxide inclusions
Green Calcite
Calcium Carbonate (CaCO3)
Dyed Agate (Tumbled)
Silicon Dioxide (SiO2) - stained microcrystalline quartz
Amber
Succinite (a fossilized organic resin)
Blue Chalcedony
Silicon Dioxide (SiO2)
Dyed Agate
Silicon Dioxide (SiO2)
Agate
Chalcedony (Silicon Dioxide, SiO2)
Satin Spar (often marketed as Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Geode (Unopened)
Crystalline Quartz Geode (SiO2)
Chert (often found as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Greenstone (Greywacke or Nephrite Jade variant)
Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)
Celestite (Celestine)
Strontium sulfate (SrSO4)
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Carnelian Agate
Silicon Dioxide (SiO2)
Jasper
Silicon dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)