Basalt with Iron Oxide staining
Basalt (Mafic volcanic rock)
igneous
Category
Mineral Based Alloy (Anthropogenic)
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Limestone
Calcium Carbonate (CaCO3)
sedimentary
Quartz with Mica (Gneissic or Pegmatitic origin)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(F,OH)2)
metamorphic
Granite
Phaneritic Igneous Rock (Granite)
igneous
Porphyritic Pink Granite
Phaneritic Porphyroid Granite
igneous
Granite
Granite (Phaneritic igneous rock)
igneous
Dendritic Agate
Silicon Dioxide with Manganese or Iron Oxide inclusions (SiO2 + Mn/Fe)
mineral
Sagenitic Agate (with Goethite/Rutile inclusions)
Silicon Dioxide (SiO2) with hydrous ferric oxide inclusions
mineral
Granite
Phaneritic Igneous Rock (Granite)
igneous
Basalt and Quartz Pebble
Basalt (Igneous) and Quartzite/Quartz (SiO2) pebble
igneous and sedimentary
Chert (River Pebble)
Microcrystalline silica (SiO2)
sedimentary
Sandstone (Quartz-rich)
Clastic sedimentary rock (SiO2 primary)
sedimentary
Granite
Granite (Silicic Plutonic Rock)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Red Granite
Phaneritic Felsic Igneous Rock (Granite)
igneous
Basalt with Vesicle/Vug
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Garnet Schist
Almandine Garnet-Mica Schist (X₃Y₂(SiO₄)₃)
metamorphic
Chert (Flint variety)
Chert (SiO2)
sedimentary
Diorite
Diorite
igneous
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
igneous
Basalt
Basalt
igneous
Basalt
Basalt
igneous
Basalt (River Cobble)
Mafic Igneous Basalt (composed primarily of Plagioclase feldspar, Pyroxene, and Olivine)
Igneous
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
igneous
Granite
Granite (consisting mainly of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Biotite Schist
Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)
metamorphic
Sandstone (Weathered Pebble)
Arenite (primarily SiO2)
sedimentary
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Mica Schist
Mica Schist (Quartz-Biotite-Muscovite Schist)
metamorphic
Basalt with Quartz Vein
Aphanitic Mafic Igneous Rock with Silicon Dioxide (SiO2) intrusion
igneous
Shale
Shale (clay-rich mudstone)
sedimentary
Granite
Granite (Phaneritic Acid Igneous Rock)
igneous
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
Mineral
Sandstone (with Quartz Vein/Inclusion)
Arenite (primarily SiO2)
sedimentary
Sandstone (Quartzite Pebble)
Arenite / Metamorphosed Sandstone (SiO2)
sedimentary
Mica (Muscovite)
Muscovite, KAl2(AlSi3O10)(OH)2
Mineral
Basalt with Quartz/Calcite Inclusion
Aphanitic Mafic Igneous Rock (Basalt) with SiO2 or CaCO3 vein
igneous
Quartz Druzy on Agate (River Cobble)
Silicon Dioxide (SiO2)
Mineral / Sedimentary (often associated with volcanic hosts)
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
metamorphic