Sedimentary Rock (Specifically A Clastic Sedimentary Rock Formed Into A Cobble)

Limestone

CaCO3 (principally composed of Calcite)

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Turquoise

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

Phyllite

Phyllite (Foliated metamorphic rock)

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Concretion with Quartz Veining

Septarian Concretion (CaCO3 / SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Chalcedony (Botryoidal)

Silicon Dioxide (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Quartzite

Quartzite (Primary mineral: SiO2)

Gneiss

Gneiss (High-grade metamorphic rock)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Chert (Yellow/Brown Jasper)

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Garnet Schist

Garnet-bearing Mica Schist (variety of compositions, often Al2SiO5 with X3Y2(SiO4)3)

River Rock (Greywacke/Siltstone)

Siltstone / Argillaceous Greywacke

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Chert (Tan/Grey variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron inclusions

Agate (specifically Botswana or Lake Superior style chalcedony)

Silicon Dioxide (SiO2)

Chert (Jasper/Quartzite variety)

Microcrystalline Silica (SiO2)

Ironstone Concretion / Goethite-Hematite Nodule

Goethite/Hematite (α-FeO(OH) / Fe2O3)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (and its variety Flint)

Silicon dioxide (SiO2) / Microcrystalline quartz

Ironstone Concretion (Boji Stone/Moqui Marble type)

Goethite/Hematite-encrusted Sandstone Concretion

Tree Agate

Dendritic Chalcedony (SiO2)

Chert (Flint nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

Chert (Green variety)

Silicon Dioxide (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Jasper (Limonite-stained Chert)

Silicon Dioxide (SiO2) with Limonite/Goethite inclusions

Quartz Druzy Geode Fragment

Silicon Dioxide (SiO2)

Diabase

Diabase (also known as Dolerite)

Sparkling Druzy Quartz on Matrix

Silicon Dioxide (SiO2) with iron oxide inclusions

Mixed Tumbled Gemstones and River Rocks

Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)

Red Jasper (Brecciated Jasper)

SiO2 (Silicon Dioxide) with Ferric Iron inclusions

Dragon Vein Agate

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Gneiss with Quartz Vein

Gneiss containing Quartz (SiO2) filler

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)