Likely weathered chert or siliceous shale
Cryptocrystalline quartz (SiO₂), possibly with clay minerals
sedimentary
Category
Mineral (Biogenic Replacement)
Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.
Tumbled picture jasper
Microcrystalline quartz (SiO₂), commonly with iron-oxide and clay inclusions
mineral
Polished orbicular jasper (likely ocean jasper)
Silica-rich chalcedony/quartz aggregate with microcrystalline quartz, commonly containing feldspar and iron-oxide inclusions
mineral
Fossilized Coral
Anthozoa
fossil
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Galena
Lead sulfide (PbS)
mineral
Iron-stained chert or siliceous mudstone
Microcrystalline quartz (SiO₂), likely chert with hematite/goethite staining
sedimentary
Galena
Lead Sulfide (PbS)
mineral
Poppy Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
sedimentary
Specular Hematite
Hematite (Iron(III) oxide, Fe2O3)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Bivalve Fossil (Clam)
Class Bivalvia (e.g., Exogyra or Gryphaea species)
fossil
Cowrie Shell Fossil
Cypraea sp.
fossil
Pyrite
Iron sulfide (FeS2)
mineral
Pyrite and Calcite (or Barite) Specimen
Iron Sulfide (FeS2) with Calcium Carbonate (CaCO3)
mineral
Mineral and Rock Collection (Assorted)
Mixed collection including Quartz (SiO2), Jasper (SiO2 with impurities), Rose Quartz, and Aventurine
mineral
Galena
Lead(II) sulfide (PbS)
mineral
Weathered iron-rich chert or jasper
Microcrystalline quartz (SiO₂), commonly colored by iron oxides/hydroxides
sedimentary
Polished orbicular jasper / brecciated jasper bead bracelet
Jasper, microcrystalline quartz (SiO₂), with variable iron oxides and other silicate inclusions
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Fossilized shell or coral fragment
Indeterminate biogenic carbonate; likely calcite/aragonite (CaCO₃)
fossil
Fossilized shark teeth in sedimentary matrix
Elasmobranchii teeth, chiefly shark; calcium-phosphate apatite (hydroxyapatite)
fossil
White coral limestone (probable fossiliferous limestone)
Calcite (CaCO₃), commonly derived from aragonitic coral skeletons recrystallized to calcite
sedimentary
Rodonite
Rhodonite (MnSiO3)
mineral
Fossil Coral / Crinoid Stem section
Anthozoa / Crinoidea fossil
fossil
Tooth or shell fragment (likely fossilized marine material)
Indeterminate; possibly a fossil fish tooth or mollusk shell fragment composed mainly of calcium carbonate (CaCO₃)
fossil
Botryoidal Chalcedony
Silicon Dioxide (SiO2)
mineral
Orbicular jasper
Siliceous microcrystalline quartz (chalcedony), commonly sold as ocean jasper
rock
Polished ocean jasper (orbicular jasper)
Silicified volcanic rock; chiefly microcrystalline quartz/chalcedony (SiO₂), with iron oxides and other alteration minerals
sedimentary
Polished ocean jasper (orbicular jasper)
Silicified microcrystalline quartz/chalcedony (SiO₂), commonly with iron oxides and other inclusions
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Murex Fossil
Muricidae (Calcium Carbonate fossilization)
fossil
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Fossil Snail
Gastropoda (fossilized)
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Fossil bivalve shell
Fossilized marine bivalve; exact genus/species indeterminate from the photograph
fossil
Triceratops Fossil
Triceratops horridus
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Shark Tooth
Selachimorpha fossil
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral