Sedimentary Or Igneous (Host Environment)

Pyrite in Matrix (Fool's Gold)

Iron Disulfide (FeS2)

Quartz Geode

Crystalline Quartz (SiO2) within a sedimentary/igneous host

Fine-grained gray sandstone or quartz-rich sedimentary pebble

Likely quartz arenite or lithic sandstone; exact identification requires microscopy or testing

Quartz with impurities or Host Rock

SiO2 (Silicon Dioxide) with mixed silicates

Basalt pebble

Aphanitic Mafic Igneous Rock

Geode with Quartz Crystals

SiO2 (Silicon Dioxide) in a geode formation

Pyrite Cubes in Matrix

Iron Disulfide (FeS2) in Host Matrix

Yellow Calcite (Carved Egg)

Calcite (Calcium Carbonate, CaCO3)

Quartz Druzy on Matrix

Silicon Dioxide (SiO2)

Lightning Stone / Fulgurite-impregnated or Septarian-like Agate

Silicon dioxide (Quartz/Chalcedony) with host rock matrix

Quartz / Agate Nodule

Silicon Dioxide (SiO2)

Rounded river pebble

Indeterminate lithic clast; likely weathered sandstone or quartz-rich sedimentary rock

Quartz Pebble

Silicon Dioxide (SiO2)

Emerald in Matrix

Beryl (Be3Al2Si6O18)

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Quartz Geode

Silicon Dioxide (SiO2) - Crystalline Quartz

Quartz-veined Metamorphic Pebble

Silicate-rich metamorphic rock with quartz veins (SiO2)

Milky quartz-rich rock

Quartz, SiO₂; possibly quartzite or massive vein quartz

Quartz Veined Mudstone

Metasedimentary rock with Quartz (SiO2) veins

Quartz Pebble with Drusy/Crystalline Pocket

Silicon Dioxide (SiO2)

Quartz-veined Sandstone

Sedimentary rock with quartz vein (SiO2)

Iron-rich quartz pebble

Quartz (SiO₂) with iron-oxide staining or inclusions; exact identification is uncertain from the photo

Quartz crystal-bearing rock

Quartz (SiO₂), likely a milky/clear quartz vein specimen

Likely rough quartz fragment

Quartz (SiO₂), possibly iron-stained or included quartz

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Shale

Fissile Mudstone

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Weathered granite or granitic gneiss pebble

Granite; primarily quartz, feldspar, and mica (exact identification is uncertain from the image)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Likely garnet-bearing metamorphic rock

Garnet amphibolite or garnet-bearing schist; chiefly almandine garnet (Fe₃Al₂Si₃O₁₂) with amphibole, mica, and quartz

Weathered sandstone or quartz-rich sedimentary rock

Likely quartz arenite or feldspathic sandstone; exact identification requires testing

Pyrite in Matrix

Iron Sulfide (FeS2)

Biotite-rich schist (likely mica schist)

Mica schist; predominantly quartz, biotite mica, and feldspar

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Tumbled jasper

Microcrystalline quartz (chalcedony), predominantly SiO₂, with iron-oxide inclusions

Quartz Vein in Host Rock

Quartz (SiO2) in Mafic or Sedimentary Matrix

Quartz (Druzy) on Matrix

Silicon Dioxide (SiO2)

Quartz (White Pebble) and Sandstone (Brown/Tan Fragments)

Silicon Dioxide (SiO2) for the white pebble

Quartz pebble

Silicon dioxide (SiO2)

Quartz (Milky/Common Quartz)

Silicon Dioxide (SiO2)

River Pebble (Gneiss or Quartzite mixture)

Metamorphic rock (Commonly Gneissic)