Sedimentary Or Metamorphic Derived

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Blue Agate (Dyed Chalcedony)

Silicon Dioxide (SiO2)

Yellow Agate

Agate (Microcrystalline Silicon Dioxide, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Rutilated Quartz

Quartz (SiO2) with Rutile (TiO2) inclusions

Green Aventurine and Clear Quartz

Green Aventurine (Silicon Dioxide - SiO2 with Fuchsite inclusions); Clear Quartz (Silicon Dioxide - SiO2)

Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)

Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Mixed Agate and Lapis Lazuli Bracelet

Chalcedony (SiO2) and Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Weathered Quartzite or Chert Pebble

Silicon Dioxide (SiO2)

River Pebble (Likely Quartzite or Chert)

Silicon Dioxide (SiO2)

Glacial Erratic (Sandstone/Quartzite)

Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)

Hag Stone (Holed Quartzite Pebble)

Quartzite (SiO2 based) with natural vug or erosion hole

Quartzite with inclusions or a banded chert

Quartzite or Chert

Limonite-stained Quartz / Quartzite

Silicon Dioxide (SiO2) with iron hydroxides (FeO(OH)·nH2O)

Brecciated Limestone or Marble Pebble

Breccia / Calcite (CaCO3)

River Cobble (likely Quartzite or Limestone)

SiO2 (Quartzite dominant) or CaCO3 (Limestone dominant)

Pyrite (or Fool's Gold)

Pyrite (FeS₂)

Dendritic Agate

Chalcedony (SiO2) with manganese/iron oxide inclusions

Yellow Quartz (Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

River Cobble (likely Sandstone or Siltstone type)

Sandstone or Siltstone (common rock types that form river cobbles)

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Orange Quartz with Epidote

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate hydroxide (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))

Quartz (likely milky/gray variety)

Quartz (SiO₂)

Calcite

Calcite (Calcium Carbonate, CaCO3)

Quartz (possibly milky quartz or quartz with inclusions)

SiO2 (Silicon Dioxide)

Agate

Agate (a cryptocrystalline variety of Quartz, SiO₂)

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Quartz

Silicon Dioxide (SiO2)

Quartz / Quartzite Fragment

Silicon Dioxide (SiO2)

Quartz Geode

Crystalline Quartz (SiO2) within a sedimentary or volcanic host

Tiger's Eye and Carnelian Quartz

Silicon Dioxide (SiO2)

Milky Quartz with Iron Inclusions

Quartz (Silicon Dioxide, SiO2)

Amethyst (Chevron or Banded Amethyst)

Silicon Dioxide (SiO2) with iron impurities

Quartz (Rock Crystal)

Quartz (SiO₂ - Silicon Dioxide)

Micaceous Sandstone or Quartzite

Sandstone (lithified quartz grains, often with mica) or Quartzite (metamorphosed sandstone)

River Pebble (likely Quartzite or Chert)

Silicon Dioxide (SiO2) crystal conglomerate

Unidentified River Rock or Mudstone

N/A (Generic rock fragment)

River Pebble (Quartzite/Siltstone mixture)

Silicon Dioxide (SiO2) mixture with varied clastic minerals

River Pebbles (Sandstone and Quartzite)

SiO2 (Quartz) dominated clastic rocks

Quartzite Chert Pebble

Microcrystalline Silicon Dioxide (SiO2)