Beach Pebble (likely Basalt or Chert)
Volcanic Basalt / Microcrystalline Quartz
igneous
Category
Rock (Likely Sedimentary)
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Green Banded Agate
Cryptocrystalline microcrystalline Quartz (SiO2)
sedimentary
Pink Granite
Phaneritic intrusive igneous rock (Feldspar-Quartz-Mica)
igneous
Chalcedony Nodule in Matrix
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Leopard Skin Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
sedimentary
Rose Quartz with Oxide Inclusions
Silicon Dioxide (SiO2)
mineral
Pink Granite (Potassium-rich)
Phaneritic Felsic Igneous Rock (K-Feldspar Granite)
igneous
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Andesite Porphyry
Andesite (extrusive volcanic rock)
igneous
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Sedimentary or Metamorphic (low-grade)
Granite
Granite; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Fossiliferous Sedimentary Rock
Sedimentary Rock with Invertebrate Fossil Imprint
fossil
Polished limestone or marble slab
Calcite-rich carbonate rock; likely marble (CaCO₃)
metamorphic
Weathered granite or granitic gneiss pebble
Granite; mainly quartz (SiO₂), feldspar, and mica, with possible gneissic alteration
igneous
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Rounded quartz-rich river pebble
Quartz (SiO₂), likely derived from quartzite or granitic rock
igneous
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper Beads (Polished)
Silicon Dioxide (SiO2)
sedimentary
Chalcedony (Agate/Blue Quartzite)
Silicon Dioxide (SiO2)
mineral
Granite (Weathered)
Phaneritic Felsic Igneous Rock
Igneous
Granite
Phaneritic Plutonic Felsic Rock
igneous
Milky Quartz (or Iron-Stained Quartz)
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Mineral or Sedimentary Rock (with mineral inclusions)
Chert (Jasper variety)
Chert (Silicon Dioxide, SiO2)
sedimentary
Chalcedony (Botryoidal or Tumbled)
Chalcedony (SiO₂)
mineral
Quartz Geode with Chalcedony
Crystalline Silicon Dioxide (SiO2)
sedimentary
Fossil Rugose Coral (Horn Coral)
Order Rugosa (likely Grewingkia or Heliophyllum species); Calcium Carbonate (CaCO3)
sedimentary
Siltstone / Fine-grained Graywacke
Argillaceous siltstone
sedimentary
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Milky Quartz with inclusions
Quartz (Silicon Dioxide, SiO2)
mineral
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with iron oxide Fe2O3 cement)
sedimentary
Rhyolite Cross Pendant
Rhyolite (High-silica volcanic rock)
igneous
Granite Cobble
Phaneritic Felsic Intrusive Rock (Granite)
igneous
Vesicular Basalt with Calcification
Vesicular Basalt (Aphanitic extrusive igneous rock)
igneous
Basalt (Polished River Stone)
Mafic Volcanic Rock (primarily Plagioclase and Pyroxene)
Igneous
Fossilized cylindrical shell or bone fragment
Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone
fossil
Small tumbled dark stone, possibly basalt or slag
Likely fine-grained basalt; exact identification is uncertain from the photograph
igneous