Mixed: Igneous And Sedimentary

Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)

Silicon Dioxide (SiO2) or Mafic extrusive igneous rock

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

White Quartz Pebble

Silicon Dioxide (SiO2)

Moonstone

Orthoclase/Albite (KAlSi3O8 / NaAlSi3O8) with Adularescence

River Cobble (likely Basalt or Chert)

Siliceous River Rock / Microcrystalline Quartz / Mafic Igneous

Barite Rose on Marcasite

Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Native Sulfur

Sulfur (S)

Green Fluorite (likely synthetic or heat-treated for jewelry)

Calcium Fluoride (CaF2)

Milky Quartz

Silicon Dioxide (SiO2)

Laterite

Laterite (no specific mineral formula as it's a rock type)

Chert (Jasper/Agate variety)

Cryptocrystalline Quartz (SiO2)

Sandstone (Quartzite-rich Cobble)

Clastic sedimentary rock (primarily SiO2)

Sandstone Concretion with Quartz Center

Sedimentary Clastic Rock (SiO2 matrix with Quartz core)

Druzy Quartz on Host Rock

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2)

Chert (Limestone-based)

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Obsidian and Green Calcite

Volcanic Glass and Calcium Carbonate (CaCO3)

Quartz (River Pebble)

Quartz (SiO₂ - Silicon Dioxide)

Yellow Quartz (Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble (Iron-Stained)

Silicon Dioxide (SiO2)

Sandstone (Pebble/Cobble)

Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)

Green Calcite

Calcite (CaCO3)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Carnelian

SiO2 (Silicon Dioxide) - Translucent Chalcedony

Calcite

Calcite (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Ferruginous Quartz (Iron-stained Quartz)

Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Fe2O3 staining)

Peridot and Citrine Gemstones (in a ring setting)

Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)

Chert (Hagstone/Gasket Rock variant)

Chert (SiO2)

Limonite (Iron Stone)

Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O