Rock (Likely Sedimentary)

Likely tumbled sandstone or limestone

Quartz-rich sandstone (possibly calcarenite/limestone)

Jasper and Ironstone (likely Jasperized Ironstone)

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)

Sandstone

Sedimentary Rock (Quartz arenite)

Sandstone pebble

Sandstone (Quartz-rich Arenite)

Chert

Microcrystalline Quartz (SiO2)

Sandstone (Quartzite Pebble)

Arenite (primarily SiO2)

Chert (Jasper)

Silicon Dioxide (SiO2)

Fossiliferous limestone, possibly containing a brachiopod or bivalve fossil

Calcite-rich limestone (CaCO₃), with an apparent shell impression or shell fragment

Pearl

Pearl; primarily aragonite (CaCO₃) in nacre

Limonite Concretion

FeO(OH)·nH2O (Hydrated Iron Oxide)

Tumbled yellow jasper or serpentine

Jasper: microcrystalline quartz (SiO₂); possible serpentine: Mg₃Si₂O₅(OH)₄

Sandstone (Weathered / Crushed)

Quartz Sandstone

Jasper

Silicon dioxide (SiO2) with iron impurities

Chert (Iron-rich or Slate-like variant)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Jasper and Agate Mix

Silicon dioxide (SiO2) - Microcrystalline Quartz

Banded Agate with Drusy Quartz

Cryptocrystalline Quartz (SiO2) with macrocrystalline Quartz

Travertine

Travertine (CaCO3)

Sandstone

Arenite (SiO2 based)

Sandstone Pebble

Sedimentary Rock (Quartzose Sandstone)

Honey calcite (orange calcite)

Calcite — calcium carbonate, CaCO₃

Chert (Sedimentary Rock)

Silicon Dioxide (SiO2)

Epidote (likely Pistacite in Epidosite rock)

Epidote: Ca2(Al,Fe)3(SiO4)3(OH)

Sandstone or Mudstone

Sedimentary Rock (Sandstone/Mudstone)

River Stone (Basalt or Siltstone)

Mafic Volcanic Rock or Clastic Sedimentary Rock

Quartz

Silicon Dioxide (SiO2)

Sandstone

Sedimentary Clastic Rock (Quartz-rich)

Quartz Vein in Basalt or Sedimentary Host Rock

Silica-veined lithic fragment (SiO2 in host matrix)

Chert

Chert (variant of microcrystalline quartz)

Polished black stone, likely black obsidian

Obsidian (volcanic glass), primarily silica-rich rhyolitic composition

Polished orbicular jasper (likely ocean jasper)

Silicified microcrystalline quartz/chalcedony with iron-oxide-rich orbicules; commonly called Ocean Jasper

Likely iron-rich slag or weathered ironstone

Hematite–goethite-rich material (Fe₂O₃/FeO(OH)); possibly industrial iron slag

Sandstone

Quartzose Sandstone (Sedimentary Rock)

Sandstone

Arenite (Siliclastic sedimentary rock)

Jasper

Microcrystalline quartz (SiO2)

Calcite-rich limestone fragment

Limestone, predominantly calcite (CaCO₃), possibly micritic or fossiliferous

Red Jasper (with Quartz inclusion)

Silicon Dioxide (SiO2) with Iron Oxide impurities

Red Jasper (possibly with Hematite/Magnetite inclusions)

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (specifically var. Flint or Jasper-rich Breccia)

Microcrystalline Quartz (SiO2)

Chert (specifically Iron-stained or Jasperoid Chert)

Microcrystalline Quartz (SiO2)

Fossiliferous Chert (with Fossil Shells)

Silicon Dioxide (SiO2) with biogenic inclusions

Chert (River Pebble)

Microcrystalline Quartz (SiO2)