Sedimentary Or Igneous (Secondary Formation)

Calcite with iron staining

Calcium Carbonate (CaCO3)

Chalcedony

Chalcedony (SiO2)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Jasper

Silicon dioxide (SiO2)

Optical Calcite

Calcium Carbonate (CaCO3)

Quartz Geode

Silicon Dioxide (SiO2)

Banded Agate

Silicon Dioxide (SiO2) - Chalcedony

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous schist/gneiss; composition likely quartz, feldspar, mica, and altered mafic minerals

Sandstone with Secondary Mineral Encrustation

Arenite with Silica/Calcite deposits (SiO2 or CaCO3)

Limonite or Ironstone Nodule

Hydrated iron oxide-hydroxide (FeO(OH)·nH2O)

Limonite Nodule

FeO(OH)·nH2O (Hydrated iron oxide-hydroxide)

Limonite Nodules / Goethite

Hydrated Iron Oxide-Hydroxide (FeO(OH)·nH2O / Fe2O3·nH2O)

Yellow Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Optical Calcite

Calcite (Calcium Carbonate, CaCO3)

Sandstone Concretion with Quartz Center

Sedimentary Clastic Rock (SiO2 matrix with Quartz core)

Mineral and Rock Collection (Assorted)

Mixed collection including Quartz (SiO2), Jasper (SiO2 with impurities), Rose Quartz, and Aventurine

Quartz Geode (with Calcite influence)

Silicon Dioxide (SiO2) with possible Calcium Carbonate (CaCO3)

Yellow Calcite

Calcite (Calcium Carbonate, CaCO3)

Geode

Quartz / Chalcedony nodule

Carnelian

SiO2 (Silicon Dioxide) - Translucent Chalcedony

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2)

Agate

Silicon dioxide (SiO2)

Agate (translucent water-worn pebble)

Cryptocrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Milky Quartz Pebble with Chert

Silicon Dioxide (SiO2)

Brecciated Jasper

Silicon Dioxide (SiO2) with iron impurities

Siltstone with Fossil Cast

Sedimentary Rock (Siltstone / Fine-grained Sandstone)

Dalmatian Jasper

Peralkaline Quartz-Feldspar Rock with Arfvedsonite

Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)

AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition

Quartz Geode

Silicon Dioxide (SiO2)

Limonite with Trace Fossils

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Clear Quartz

Silicon dioxide (SiO2)

Quartz Druze (Crystalline Quartz)

Silicon Dioxide (SiO2)

Geode

Quartz nodule / Chalcedony-lined cavity

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Jasper or Chert with Quartz Vugs

Silicon Dioxide (SiO2)

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Geode

Quartz / Chalcedony nodule

Agate

Agate (Silicon Dioxide, SiO2)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Polished orbicular stone, likely granite or diorite

Granite–diorite, composed mainly of feldspar, quartz, and dark amphibole/biotite

Garnet in Host Rock

Garnet Group (A3B2(SiO4)3)