Igneous, Sedimentary, Metamorphic, Mineral, Gemstone, Fossil, Or Meteorite

Ironstone Concretion

Ironstone (Limonite/Goethite/Hematite mixture)

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

Blue Apatite

Ca5(PO4)3(F,Cl,OH)

Apatite

Calcium phosphate fluoride/chloride, Ca5(PO4)3(F,Cl,OH)

Siderite Concretion

Ironstone (Siderite) Concretion, FeCO3

Olivine in Quartz/Feldspar Matrix (Peridotite or Granitic Pegmatite)

(Mg,Fe)2SiO4 (Olivine) with Quartz / Feldspar

Graphite

Graphite (Chemical Formula: C)

Clear Quartz

SiO2 (Silicon Dioxide)

Weathered quartz-rich pebble

Likely quartz-bearing granitoid or quartz vein fragment; exact identification requires testing

Ironstone Concretion

Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)

Peridot

Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4

Sandstone concretion

Arenite sedimentary rock (concretion/nodule)

Blue Apatite

Apatite (Ca5(PO4)3(F,Cl,OH))

Likely hematite-rich ironstone or metallic mineral fragment

Hematite (Fe₂O₃), possibly with magnetite (Fe₃O₄) or metallic iron

Ironstone Concretion (Iron-rich Mudstone)

Siderite / Geothite concretion (FeCO3 / FeO(OH))

Weathered granitic or metamorphic rock fragment

Indeterminate; likely quartz–feldspar–mica-bearing granitoid or gneiss

Apatite

Ca5(PO4)3(F,Cl,OH)

Concretion

Sedimentary Concretion

Fossil shark tooth

Likely fossilized shark tooth, possibly *Carcharocles* or *Otodus* species

Pyrite

Iron Sulfide (FeS2)

Blue Apatite

Fluorapatite (Ca5(PO4)3(F,Cl,OH))

Pyrite (Iron Pyrites)

Iron Sulfide (FeS2)

Feldspar

Feldspar (Orthoclase/Microcline)

Quartz with Inclusions

Silicon Dioxide (SiO2)

Yellow Apatite

Fluorapatite (Ca5(PO4)3(F,Cl,OH))

Fossil-bearing fine-grained sedimentary rock

Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein

Ironstone Concretion

Siderite or Hematite-rich Concretion (FeCO3 / Fe2O3)

Fossilized marine shell fragment

Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)

Concretion

Calcareous or ferruginous concretion

Oyster shell fragment

Ostreidae shell; primarily calcite (CaCO₃)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Petrified wood

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing organic tissue

Polished fossil coral

Fossilized coral, commonly agatized coral (silica replacing CaCO₃)

Dark metallic mineral specimen, possibly hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄); exact identification requires testing

Iron Concretion

Iron oxide concretion (Hematite or Goethite)

Small dark tumbled stone (likely basalt or iron-rich mineral)

Uncertain; possibly basalt (fine-grained plagioclase–pyroxene rock) or magnetite-rich material (Fe₃O₄)

Weathered iron-rich rock fragment

Indeterminate; likely limonite/goethite-bearing sandstone or laterite

Pyrite

Iron Sulfide (FeS2)

Ironstone Concretion

Ferruginous Siltstone/Ironstone (Fe2O3)

Claystone Concretion

Septarian Concretion (Ironstone-rich)

Pyrite

Iron Sulfide (FeS2)

Blue Apatite

Ca5(PO4)3(F,Cl,OH)