Diabase (Greenstone)

Diabase or Dolerite

igneous

Pink Granite (Water-worn Cobble)

Phaneritic Felsic Intrusive Igneous Rock

igneous

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

mineral

Gneiss (Metamorphic Cobble)

Gneiss

metamorphic

Basalt with Quartz Veins

Vesicular or aphanitic Basalt with SiO2 (Quartz) intrusions

Igneous

Chert (Jasper/Flint Pebble)

Microcrystalline quartz (SiO2)

sedimentary

Unakite

Epidotized Granite

metamorphic

Coquina / Fossiliferous Limestone

Bioclastic Limestone (CaCO3)

sedimentary

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

sedimentary

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

sedimentary

Sandstone

Clastic sedimentary rock (primarily SiO2)

sedimentary

Pumice

Vesicular volcanic glass

igneous

Diorite

Diorite

igneous

Quartzite

Quartzite (primarily SiO2)

metamorphic

Granite

Granite (Felsic Plutonic Rock)

igneous

River Stone (Basalt)

Basalt (Aphanitic Mafic Igneous Rock)

igneous

Granite

Phaneritic Plutonic Felsic Rock (SiO2 > 63%)

igneous

Sandstone (with differential weathering)

Arenite / Quartz Sandstone (SiO2)

sedimentary

Jasper

Silicon dioxide / Chalcedony (SiO2)

Sedimentary

Gneiss (Granitic Gneiss)

Gneiss

metamorphic

Bumblebee Jasper

Fossiliferous Volcanic Rock (composed of Calcium Carbonate, Manganese Oxides, and Arsenic Sulfides)

igneous

Hypersthene

Hypersthene (Magnesium Iron Silicate - (Mg,Fe)SiO3)

mineral

Bronzite

Enstatite (var. Bronzite), (Mg,Fe)SiO3

mineral

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

sedimentary

Pink Granite

Phaneritic Felsic Igneous Rock

igneous

Granite Cobble

Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)

igneous

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

sedimentary

Garden Quartz (Lodalite)

Silicon Dioxide with various mineral inclusions (SiO2)

mineral

Garden Quartz (Lodalite)

Silicon Dioxide (SiO2) with various inclusions

mineral

Carnelian Agate

Chalcedony (SiO2 with Iron Oxide impurities)

mineral

Quartz Geode Fragment

Silicon Dioxide (SiO2)

mineral

Granite

Phaneritic Felsic Igneous Rock

igneous

Conglomerate

Conglomerate (Sedimentary rock containing rounded clasts)

sedimentary

Limonite Pseudomorph after Pyrite

Limonite (Hydrous iron oxides e.g., FeO(OH)·nH2O) pseudomorphing Pyrite (FeS2)

mineral

Shale

Fissile Mudrock (Clay-rich Sedimentary Rock)

sedimentary

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (primarily SiO2)

metamorphic

Smoky Quartz

Silicon Dioxide (SiO2)

mineral

Obsidian

Obsidian (Volcanic Glass)

igneous

Clear Quartz

Silicon Dioxide (SiO2)

mineral

Obsidian

Obsidian (Volcanic Glass)

igneous

Chert / Flint

Chert (SiO2)

sedimentary

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)

metamorphic