Mineral, Specifically A Rock Fragment

Likely weathered quartz-rich rock fragment

Uncertain; possibly granitic pegmatite or quartz-bearing metamorphic rock

Banded Agate (Geode Fragment)

Silicon Dioxide (SiO2) - Variety Agate

Druzy Quartz on Sandstone

Silicon Dioxide (SiO2) on Sedimentary Host Rock

Sandstone with Iron Banding

Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)

Possible weathered quartz-rich rock or iron-stained mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide inclusions

Banded Agate

Chalcedony / Silicon Dioxide (SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2

Uncertain small metallic-looking mineral/rock fragment

Indeterminate; possibly galena-bearing rock or metallic slag

Dendritic Agate (specifically Orange/Tumbled)

Silicon Dioxide (SiO2) with Oxide Inclusions

Granite

Plutonic felsic igneous rock

Quartz Pebble

Silicon Dioxide (SiO2)

Fire Opal (in Matrix)

Hydrated Silica (SiO2·nH2O)

Polished brown mineral fragment, likely quartz-rich iron-stained material

Possibly quartz (SiO₂) with iron-oxide inclusions; exact identification is uncertain from the image

Fossil Coral (Petoskey-style Rugose Coral)

Hexagonaria percarinata (Order: Rugosa)

Hag Stone

Perforated Sedimentary Rock (typically Limestone or Sandstone)

Breccia

Breccia

Milky Quartz

Silicon Dioxide (SiO2)

Weathered sandstone or volcanic rock fragment

Indeterminate; likely quartz–feldspar-rich sandstone, possibly altered volcanic rock

Rough Black Diamond (Bort / Carbonado)

Diamond (C)

River Pebble (Granitic Sandstone)

Clastic sedimentary rock (Lithic Arenite)

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Banded agate or jasper fragment

Microcrystalline quartz, SiO₂ (likely iron-stained chalcedony)

Possible weathered mica-rich metamorphic fragment

Mica schist or phyllite (quartz–mica assemblage; identification uncertain from image)

Pink Granite

Phaneritic Felsic Igneous Rock

Likely milky quartz fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide or mica inclusions

Sandstone

Sedimentary Rock (Quartz arenite/Arkose)

Gravel and Sediment Sample

Mixed clastic sediment

Quartz Geode

Crystalline Silicon Dioxide (SiO2) within a geode structure

Quartz (Citrine or Iron-Stained variety)

Silicon Dioxide (SiO2)

Serpentine

Serpentine Group (Mg3Si2O5(OH)4)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Dalmation Stone (often called Dalmatian Jasper)

Antiperthite-rich Microgranite

Ocean Jasper

Orbicular Jasper / Chalcedony (SiO2)

Chert (specifically Flint or Gray Chalcedony)

Microcrystalline Quartz (SiO2)

Dalmatian Stone (Dalmation Jasper)

Aplite with Arfvedsonite inclusions

Granite or granitic rock fragment

Felsic intrusive igneous rock, typically quartz + feldspar + mica; exact species uncertain from the image

Fossiliferous Shale

Laminated Mudrock with plant fossils

Clear Quartz Crystal

Quartz (Silicon Dioxide - SiO2)

Fossiliferous Shale

Fossiliferous Mudstone / Shale