Sedimentary (Chemically Precipitated)

Flint

SiO2 (Microcrystalline Quartz)

Orange calcite

Calcite, calcium carbonate (CaCO₃)

Calcite crystal specimen

Calcite — calcium carbonate, CaCO₃

Concretion (likely iron-rich sandstone or claystone concretion)

Diagenetic carbonate/iron-oxide concretion; exact mineralogy requires testing

Jasper with Quartz Veining

Microcrystalline quartz (SiO2) with iron oxide impurities

Orange calcite

Calcite (calcium carbonate, CaCO₃)

Honey calcite crystal fragment

Calcite (CaCO₃), likely honey or amber calcite

Limestone

Calcium Carbonate (CaCO3)

Iron-oxide-rich breccia or weathered ironstone

Hematite–goethite ironstone, likely brecciated and quartz-bearing

Iron-rich concretion or weathered ironstone pebble

Goethite/limonite-bearing ironstone; commonly an iron-oxide concretion (FeO(OH)·nH₂O, variable)

Banded Iron Formation (Fragment)

Banded Iron Formation (BIF)

Blue-green calcite

Calcite (CaCO₃), likely copper-bearing or otherwise inclusions-colored

Banded Iron Formation (BIF) / Ironstone

Magnetite-Hematite Quartzite / Ironstone

Sandstone with Iron Staining

Clastic sedimentary rock (SiO2 with iron oxides)

Limestone (or Calcite Nodules)

Calcium Carbonate (CaCO3)

Banded Flint (Chert)

Silicon Dioxide (SiO2)

Blue Apatite

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

Limestone

Calcium Carbonate (CaCO3)

Quartz / Quartzite

Silicon Dioxide (SiO2)

Dyed Agate (Dragon Vein Agate Bead)

Silicon dioxide (SiO2) variety Chalcedony

Chert (Flint / Jasper)

Microcrystalline Quartz (SiO2)

Tumbled honey calcite

Calcite (calcium carbonate, CaCO₃)

Weathered iron-rich mineral concretion

Likely limonite/goethite concretion (hydrated iron oxides), possibly a weathered ironstone fragment

Quartz Geode (Druzy Quartz)

Silicon Dioxide (SiO2)

Likely quartz-rich rock fragment

Probably microcrystalline quartz (SiO₂), possibly a pale chert or quartzite fragment

Jasper with Hematite

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Microcrystalline Limestone

Limestone (CaCO3 with impurities)

Ocean Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

Weathered iron-rich concretion or laterite fragment

Ferruginous concretion, likely goethite/limonite (hydrated iron oxides) in a clay-rich matrix

Jasper

Microcrystalline Quartz (SiO2)

Weathered limestone fragment

Limestone, predominantly calcite (CaCO₃), possibly porous bioclastic limestone

Quartz Pebble

Silicon Dioxide (SiO2)

Limonite

FeO(OH)·nH2O

Iron-rich rock, possibly limonite or goethite

Likely goethite (α-FeO(OH)) and/or limonite (iron oxides/oxyhydroxides); identification is uncertain from the image alone

Likely iron-rich metamorphic rock (possibly hematite-rich ironstone)

Uncertain from the image; possible hematite-bearing ironstone, chiefly Fe₂O₃ with associated silicate minerals

Chert Pebble

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone

Biogenic Limestone (predominantly CaCO3)

Jasper (Iron-stained Chert)

Silicon Dioxide (SiO2) with Iron Oxides

Chert (Jasper / Petrified Wood)

Microcrystalline Quartz (SiO2)

Jasper with Quartz Druzy

Silicon Dioxide (SiO2)

Quartz vein specimen

Quartz (SiO₂), likely drusy or massive quartz on host rock

Hematite

Iron(III) oxide (Fe2O3)