Carnelian Agate

Carnelian (Silicon Dioxide - SiO2 with Fe impurities)

mineral

Jasper

Jasper (Silicon Dioxide) - SiO2

sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

sedimentary

Blue Calcite

Calcium Carbonate (CaCO3)

mineral

Fossiliferous Limestone

Calcite (CaCO3) Rich Bio-sedimentary Rock

sedimentary

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

mineral

Satin Spar (Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

mineral

Iceland Spar (Optical Calcite)

Calcite (Calcium Carbonate, CaCO3)

mineral

Pyrite with Iron Oxides (Fool's Gold in Matrix)

Iron Sulfide (FeS2)

mineral

Fluorite

Calcium Fluoride (CaF2)

mineral

Quartzite

Quartzite (SiO2)

metamorphic

Chert (Common Opal variant)

Microcrystalline Quartz (SiO2)

sedimentary

Quartzite with Iron Mineral Banding

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) staining

metamorphic

Quartzite with Sandstone/Iron staining

Metamorphic Quartzite (SiO2)

metamorphic

Quartzite Pebble (with Iron Staining)

Quartzite (SiO2)

metamorphic

Quartz Vein / Milky Quartz

Silicon Dioxide (SiO2)

mineral

Satin Spar (Gypsum)

Hydrous Calcium Sulfate (CaSO4·2H2O)

mineral

Quartz Vein in Sedimentary Rock

Silicon Dioxide (SiO2) with host Chert or Limestone

mineral

Sandstone Concretion

Moqui Marble (Iron-oxide concretion)

sedimentary

Sandstone Concretion

Moqui Marble / Iron-oxide Concretion (SiO2 with Hematite/Goethite)

sedimentary

Red Jasper

Jasper (Silicon Dioxide) - SiO2

sedimentary

Red Jasper

Jasper (Silicon Dioxide, SiO2)

sedimentary

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

sedimentary

Quartz Pebble (Iron-stained)

Silicon Dioxide (SiO2)

Mineral / Sedimentary setting

Quartzite

Quartzite (SiO2)

metamorphic

Quartz Pebble (with probable Iron staining)

Silicon Dioxide (SiO2)

mineral

Ironstone Concretion (Siderite Nodules)

Siderite (FeCO3) in Mudstone or Sandstone matrix

sedimentary

Septarian Nodule (Yellow Jasper variety)

Septarian Nodule (comprising Calcite, Aragonite, and Limestone/Bentonite)

sedimentary

Ironstone Concretion

Siderite or Limonite Concretion

sedimentary

Orange Calcite

Calcium Carbonate (CaCO3)

mineral

Red Quartzite / Ferruginous Quartzite

Quartzite (SiO2 with Iron Oxide impurities)

metamorphic

Peach Moonstone (Orange/Peach Feldspar)

Potassium aluminum silicate (KAlSi3O8)

mineral

Carnelian Agate

Carnelian (Silicon Dioxide, SiO2)

mineral

Quartz (Yellow/Milky variety)

Silicon Dioxide (SiO2)

mineral

Quartz Pebble (Chalcedony/Agate)

Silicon Dioxide (SiO2)

Mineral

Quartz Pebble (Iron-Stained)

Quartz (Silicon Dioxide - SiO2)

mineral

Ironstone Concretion (Moqui Marble type)

Iron oxide concretion (Goethite/Hematite and Sandstone)

sedimentary

Chert (often called Flint)

Microcrystalline Quartz (SiO2)

sedimentary

River Siltstone Pebble

Siltstone (primarily composed of silica and clay minerals)

sedimentary

Chert (variously known as Flint or River Pebble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary

Yellow Quartzite Pebble

Quartzite (primarily SiO2)

metamorphic