Organic Material (Likely A Fruit Or Berry)

Green Common Opal

Hydrated Silica (SiO2·nH2O)

Diorite (Dalmatian Stone)

Phaneritic Plutonic Diorite

Septarian Nodule (Galt)

Calcareous concretion / Septarian concretion

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Jasper River Stone

Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)

Conglomerate with Native Copper

Clastic Sedimentary Rock with Native Copper (Cu)

Sandstone (with potential iron-oxide staining)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2)

Quartz Pebble (with probable inclusions or staining)

Quartz (Silicon Dioxide - SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Banded Agate

Agate (Cryptocrystalline variety of Silica, SiO2)

Sandstone

Arenite (primarily SiO2 - Silicon Dioxide)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Ferrous Slag

Iron/Steel Slag (Complex Calcium-Alumino-Silicates)

Limestone

Calcium Carbonate (CaCO3)

Quartzite

Quartzite (primarily SiO2)

River Cobble (likely Basalt or Metagraywacke)

Non-specific water-worn lithic fragment

Quartzite Cobble

Quartzite (primarily SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Thunderegg (specifically a Jasper/Agate-filled Geode nodule)

Silicon Dioxide (SiO2) within Rhyolitic Matrix

Diamond (in jewelry setting)

Cubic Carbon (C)

Chert

Chert (SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 based)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Ironstone (likely siderite or goethite-rich siltstone)

Ferruginous Siltstone

Peridot (Olivine)

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

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Limestone

Calcium Carbonate (CaCO3)

Sandstone (with minor quartz and possible clay components)

Clastic Sedimentary Rock (SiO2 dominated)

Sandstone (specifically Banded Sandstone)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Greywacke/Siltstone variant)

Clastic Sedimentary Rock (composed primarily of Quartz SiO2 and Feldspar)

Sandstone

Arenite (primarily SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides

Quartz Pebble

Silicon Dioxide (SiO2)

Travertine (Calcareous Tufa)

Calcium Carbonate (CaCO3)

Copper-bearing Quartz (likely Chrysocolla or Malachite staining)

Cuprite, Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) or Malachite staining on Quartz/Host Rock

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)