Marble

Serpentinite

Serpentinite (composed largely of Serpentine group minerals like Antigorite, Lizardite, and Chrysotile: Mg3Si2O5(OH)4)

Milky Quartz (Water-worn Pebble)

Quartz (Silicon Dioxide) - SiO2

Chert (specifically a weathered Chert nodule or fragment)

Chert; Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Beach Pebble)

Microcrystalline Quartz (SiO2)

River Stone (Chert/Siltstone)

Cryptocrystalline Quartz (SiO2) with trace impurities

Chert (variant Flint/Jasper)

Microcrystalline Opaline Silica (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Chert (Yellow Jasper variant)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert

Silicon dioxide (SiO2)

Chert (Flint)

Microcrystalline silica (SiO2)

Diamond

C (Native Carbon)

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Peridot

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

Pyrite

Iron Sulfide (FeS2)

Chert (and Chert Geode)

Silicon Dioxide (SiO2)

Serpentine

Antigorite, Lizardite, or Chrysotile; (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Chert (Agatized/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Rough Blue Diamond

Carbon (C)

Limestone

Calcium Carbonate (CaCO3)

Chert (specifically Flint or Common Chert)

Silicon Dioxide (SiO2)

Chert (Honey Chert or Chalcedony Pebble)

Cryptocrystalline Quartz (SiO2)

Crinoid and Coral Fossils in Limestone

Fossiliferous Limestone with Rugosa (order) and Crinoidea (class)

Banded Iron Formation (BIF)

Banded Iron Formation containing Hematite (Fe2O3) and Magnetite (Fe3O4)

Chert

Microcrystalline Quartz (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Limestone

Limestone (Calcium Carbonate - CaCO3)

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Beach Pebble)

Silicon Dioxide (SiO2)

Chert Nodules

Microcrystalline Quartz (SiO2)

Yellow Chert (Jasper)

Cryptocrystalline Quartz (SiO2)

Sandstone with Iron Oxide Staining

Arenite with Limonite/Hematite alteration

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Amber

Succinite (C10H16O)

Ironstone Concretion

Siderite or Hematite Concretion

Basalt Water-Worn Pebble

Aphanitic Mafic Igneous Rock

Diamond

Diamond (pure Carbon, C)

Sandstone (likely Arkosic or Lithic Sandstone)

Clastic Sedimentary Rock (SiO2 with assorted minerals)

Diamond

Diamond (C)

Quartz / Limestone Gravel

SiO2 (Silicon Dioxide) and CaCO3 (Calcium Carbonate)

Limestone

Calcareous sedimentary rock (CaCO3)