Organic (Geological Interest)

Weathered mica-rich rock (tentative identification)

Possibly mica schist or phyllite; exact identification requires closer examination

Polished fossiliferous agate

Chalcedony (microcrystalline SiO₂), likely containing fossil coral or stromatoporoid structures

Yellow Quartzite

Quartzite (primarily SiO2)

Quartz-veined basalt or mafic schist

Basaltic rock dominated by plagioclase–pyroxene minerals, with milky quartz/calcite veins

Ironstone Nodules / Siderite Concretion

Siderite (FeCO3) / Ferruginous Septarian Concretion

Pyrite

Iron Disulfide (FeS2)

Weathered quartz-rich pebble

Milky quartz, chiefly silicon dioxide (SiO₂), possibly with iron-oxide staining and minor feldspar

Possible weathered iron-rich rock or slag fragment

Indeterminate; likely limonite/goethite-bearing material, possibly iron slag

Shale with Limonite/Hematite Staining

Argillaceous sedimentary rock with Iron Oxides (FeO(OH)·nH2O / Fe2O3)

Milky quartz with iron-oxide staining

Quartz (SiO₂), likely massive quartz with hematite/goethite inclusions

Blue Apatite

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

Pyrite

Iron Sulfide (FeS2)

Chert Nodule

Chert (SiO2)

Quartz with Iron Oxide Staining

SiO2

Quartz Vein in Mica Schist

Quartz (SiO2) with Muscovite/Biotite Schist

Freshwater Pearl

Aragonite / Biogenic Calcium Carbonate (CaCO3)

Pyrite

Iron Sulfide (FeS2)

Rounded brown pebble

Likely iron-stained quartzite or chert; exact identification is uncertain from the photograph

Polished basalt with chalcedony/agate vein

Basalt (fine-grained mafic volcanic rock) with microcrystalline quartz, SiO₂

Rounded quartz-rich pebble, possibly weathered granite or quartzite

Indeterminate; likely quartz (SiO₂)-rich silicate rock

Rounded quartz-rich sandstone or quartzite cobble

Quartz-dominated siliciclastic rock; likely sandstone, possibly weakly metamorphosed quartzite

Iron-stained quartz-rich rock, likely brecciated quartz vein

Quartz (SiO₂) with iron oxides/hydroxides, chiefly hematite and goethite; possibly limonite

Limonite-stained Quartz

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O) coatings

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Sandstone (Ferruginous)

Arenite with iron oxide cement (Fe2O3)

Quartz-rich rock, likely smoky quartz with feldspar

Quartz (SiO₂), possibly in a granitic or pegmatitic matrix

Likely weathered limestone or calcitic marble

Calcite (CaCO₃), probably micritic limestone; marble is a possible metamorphic alternative

Red Coral (Precious Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

Weathered iron-rich concretion (probable limonite/goethite)

Limonite–goethite aggregate, approximately FeO(OH)·nH₂O

Likely galena-bearing ore or graphite-rich sulfide fragment

Indeterminate; possibly galena (PbS) with quartz, or graphite-rich schist

Iron-rich slag or weathered ironstone fragments

Probably hematite–goethite material; possibly industrial iron slag (Fe₂O₃/FeO(OH))

Chert

Chert (SiO2)

Limestone (or Calcite Pebble)

Calcium Carbonate (CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Banded Chert

Silicon Dioxide (SiO2)

Weathered sandstone fragment

Quartz-rich sandstone, likely feldspathic or lithic sandstone

Mother of Pearl and Onyx

Aragonite (Mother of Pearl) and Chalcedony (Onyx)

Iron-stained quartz pebble (probable quartzite)

Quartz (SiO₂), possibly quartzite with hematite/goethite staining

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets