Amber (fossilized tree resin)
Succinite; organic resin composed mainly of polymerized terpenoids
fossil
Category
Organic (Non Rock)
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Weathered sandstone cobble
Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
River Pebble (likely Quartzite or Chert)
Silicon Dioxide (SiO2)
metamorphic or sedimentary
Obsidian
Volcanic Glass (SiO2, usually 70% or more)
igneous
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Quartzite
Metamorphic Quartzite (predominantly SiO2)
metamorphic
Quartzite (Yellow/Tan)
Metamorphic Rock composed of Quartz (SiO₂)
metamorphic
Anthracite Coal
Low-grade metamorphic carbonaceous rock
metamorphic
Gray Quartzite River Rock
Meta-quartzite (SiO2)
metamorphic
Green Chert
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone with Iron Staining
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
sedimentary
Ferruginous Quartzite (Red Quartzite)
Quartzite (primarily SiO2 with Fe2O3 inclusions)
metamorphic
Gold Ore (in Quartz/Sulfide matrix)
Native Gold (Au) in Quartz (SiO2) and Pyrite (FeS2)
mineral
Rounded dark river pebble, likely basalt
Basalt; fine-grained mafic volcanic rock, typically plagioclase + pyroxene ± olivine
igneous
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Granite / Feldspar gravel
Granite (felsic intrusive igneous rock)
igneous
Dark fine-grained rock, likely basalt
Basalt; chiefly plagioclase feldspar and pyroxene, with possible olivine and iron-titanium oxides
igneous
Weathered iron-rich metamorphic rock, likely schist or quartzite
Provisional identification: ferruginous quartzite or mica schist; composition likely quartz (SiO₂), iron oxides/hydroxides, and mica or clay minerals
metamorphic
Ironstone Concretion (Ironstone Gourd)
Limonite/Goethite Concretion (FeOO(H))
sedimentary
Anthracite Coal
Anthracite
sedimentary
Siltstone or Fine-grained Sandstone pebble
Siltstone (primarily SiO2 with clay minerals)
sedimentary
Quartzite River Rock
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Dyed or treated turquoise-like tumbled stone
Likely turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O), though blue-green magnesite or howlite imitation is possible
mineral
Pyritic Mudstone
Argillaceous rock (FeS2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert
Chert (SiO2)
sedimentary
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Flint
Chert (Silicon Dioxide, SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Serpentine (Nephrite-like Serpentine)
Serpentinite (Hydrous magnesium iron phyllosilicate)
metamorphic
Obsidian
Volcanic Glass
igneous
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated Iron Oxide)
mineral
Quartzite Pebble
Quartzite (composed primarily of SiO2)
metamorphic
Chert (Chalcedony/Flint)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
fossil
Chert (variations include Flint or Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary