Mineral Based Human Made Alloy

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Montana Moss Agate

Chalcedony (SiO2) with Manganese/Iron oxide inclusions

Sandstone

Arenite (clastic sedimentary rock)

Chert (with Iron Staining)

Microcrystalline Quartz (SiO2)

Biotite (Mica)

Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)

Talc Schist / Soapstone

Talc (Mg3Si4O10(OH)2)

Asphalt

Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)

Sandstone Pebble (River Cobble)

Arenite (Sandstone)

Sandstone Pebble

Arenite (Clastic Sedimentary Rock)

Basalt with Weathered Crust

Aphanitic Mafic Igneous Rock (Basalt)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Bornite

Bornite (Cu5FeS4)

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Tree Agate

Silicon Dioxide (SiO2) with Chlorite inclusions

Dendritic Agate (Tree Agate)

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Labradorite/Larvikite

Plagioclase Feldspar (Na,Ca)(Al,Si)4O8

Tree Agate

Chalcedony (SiO2) with Dendritic inclusions

Bloodstone

Heliotrope (a variety of Cryptocrystalline Quartz / Jasper, SiO2)

Pink Coral

Corallium rubrum (Calcium Carbonate, CaCO3)

Snowflake Obsidian

Volcanic Glass (SiO2 rich with Cristobalite inclusions)

Fossilized Shark Tooth (Fragment)

Elasmobranchii (fossilized tooth)

Granite

Granite

Yellow Chalcedony

Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)

Granite (Weathered)

Granite (Felsic Plutonic Rock)

Red Jasper (Opaque Chalcedony)

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Blue Sapphire (Synthetic or Man-made Glass Imitation)

Corundum (Al2O3) if natural; Lead-glass or Spinal if synthetic

Chert (with Quartz Veining)

Microcrystalline Quartz (SiO2)

Pyrite

Iron Disulfide (FeS2)

Granodiorite

Granodiorite (intermediate intrusive igneous rock)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert / Flint (Yellow Jasper Variant)

Microcrystalline Quartz (SiO2 with Iron Oxide impurities)

Tree Agate

Silicon Dioxide (SiO2) with Dendritic Inclusions

Graphite

Graphite (Carbon, C)

Granite Pebble

Phaneritic intrusive igneous rock (Quartz, Feldspar, Mica)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with marine fossils

Basalt and Quartz pebbles

Basalt (extrusive igneous rock) and Quartz (SiO2)

Serpentine

Antigorite, Lizardite, or Chrysotile; (Mg, Fe)3Si2O5(OH)4

River Pebble Gravel

Hydrothermally modified Clastic Sediment (mainly Quartzite and Chert)

Spherulitic Agate / Moss Agate

Chalcedony (SiO2) with mineral inclusions

Amethyst Quartz Crystal

Silicon Dioxide (SiO2) with iron impurities

Labradorite

Labradorite ((Ca, Na)(Al, Si)4O8)

White Topaz

Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2]