Sedimentary (Base), Then Artificial

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Sandstone (Weathered Pebble)

Arenite (composed primarily of SiO2)

Sandstone

Arenite (SiO2 dominant)

Fossilized Brachiopod

Brachiopoda (e.g., Rhynchonellida or Spiriferida)

Limestone Fragment

Sedimentary rock (primarily Calcium Carbonate, CaCO3)

Limestone Pebble

Limestone (Calcium Carbonate, CaCO3)

Conglomerate

Sedimentary Conglomerate

Banded Agate

Sedimentary Cryptocrystalline Quartz (SiO2)

River Pebble

Quartzite / Weathered Sedimentary Rock

Gneiss

Gneiss (Foliated Metamorphic Rock)

Graphite

Carbon (C)

Red Sandstone

Arenite (SiO2 based with Fe2O3)

Sandstone (with Iron Staining)

Arenite (Silicon Dioxide, SiO2, often with iron oxides like Limonite)

Chert (Iron-stained)

Chert (Cryptocrystalline Silica, SiO2)

Siltstone

Siltstone (primarily SiO2 with Al2O3)

Gneiss

High-grade metamorphic rock (Gneiss)

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Vesicular basalt (likely amygdaloidal basalt)

Basalt, a mafic volcanic rock composed mainly of plagioclase feldspar, clinopyroxene, and commonly olivine; vesicles are partly mineral-filled amygdules.

Limestone

Calcium Carbonate (CaCO3)

Dalmation Stone (often called Dalmatian Jasper)

Peralkaline Rock (Microgranite/Aplite), SiO2 with inclusions of Arfvedsonite

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Chert (River Pebble)

Cryptocrystalline Quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Coarse Sandstone Pebble

Clastic Sedimentary Rock (Sandstone)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Anthracite Coal

Anthracite (Carbon-based sedimentary-metamorphic rock)

Blue Celestite (Celestine)

Strontium sulfate (SrSO4)

Granite Gneiss

Granitoid Gneiss

Chert (Nodule)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Siltstone

Siltstone (primarily SiO2 with Al2O3)

Dendritic Chert

Silicon Dioxide with Manganese Oxide Inclusions (SiO2 + MnO2)

Limestone

Calcium Carbonate (CaCO3)

Limestone Boulder

Sedimentary Rock (Calcium Carbonate, CaCO3)

Fossiliferous Limestone

Calcite (CaCO3) matrix with biogenic fragments

Limestone

Sedimentary rock composed mainly of calcite (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Limestone ( weathered ) / Chert Nodular Rock

Sedimentary rock (primarily Calcium Carbonate, CaCO3, with Microcrystalline Quartz, SiO2)

Limestone

Calcium Carbonate (CaCO3)

Vesicular Limestone with Borings

Fossiliferous Calcarenite (Calcium Carbonate, CaCO3)

Sandstone Cobble with Iron Staining

Arenite with Limonite/Hematite staining

Limestone

Calcium Carbonate (CaCO3)