Sedimentary Or Igneous Fragment

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Likely limestone or calcareous fossil fragment

Calcite-rich carbonate rock; possibly bioclastic limestone (CaCO₃)

Quartz

Silicon Dioxide (SiO2)

Porphyritic Igneous Rock / Basalt or Andesite Xenolith in Granite or Quartzite

Silicate rock with contrasting xenolith/inclusion

Gneiss (specifically Banded Gneiss)

Gneiss

Quartz

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Unidentified gray stone

Likely quartz-rich stone; exact identification is not possible from the image

Seashell Fragment

Calcium Carbonate (CaCO3) in the form of Aragonite or Calcite

Weathered limestone or calcareous sandstone

Calcite-rich carbonate rock, chiefly calcium carbonate (CaCO₃), possibly fossiliferous limestone

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)

Granite Gravel (Pebble)

Intrusive Felsic Igneous Rock

Conglomerate

Conglomerate (clastic sedimentary rock)

Likely weathered sandstone or iron-stained sedimentary fragment

Quartz-rich sandstone; exact identification requires testing

Likely weathered quartz-rich stone

Indeterminate; possibly quartz-bearing granite or milky quartz

Milky quartz (quartz-rich rock fragment)

Quartz, silicon dioxide (SiO₂)

Fossilized Bone Fragment

Permineralized Vertebrate Bone (Hydrox yapatite replaced by Silica or Calcite)

Sandstone (with concrete/human-made layer)

Clastic Sedimentary Rock (primarily Quartz/Feldspar grains)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Fossiliferous Rock (Invertebrate Fossil in Matrix)

Fossiliferous limestone or shaly matrix containing skeletal fossil remains

Concrete Fragment

Artificial Conglomerate (Cement and Aggregate)

Quartz Sand Grain / Micro Crystal

Silicon Dioxide (SiO2)

Shale fragment

Shale (Laminated Mudstone)

Conglomerate with Quartz Inclusions

Conglomerate (clastic sedimentary rock) with internal Quartz (SiO2)

Gravel (Crushed Stone Aggregates)

Mixed Siliciclastic / Carbonate Aggregate

Weathered granitic rock fragment

Granite, predominantly quartz–feldspar–mica assemblage

Weathered granite fragment

Granite; chiefly quartz (SiO₂), feldspar, and mica

Greenish translucent mineral fragment

Indeterminate; possibly serpentine, epidote, or green glassy feldspar

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Chert Breccia

Brecciated Chert

Possible weathered quartz-rich rock or iron-stained mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide inclusions

Quartz (with inclusions / Sandstone fragment)

Silicon Dioxide (SiO2)

Concretion

Sedimentary Concretion (Ironstone / Calcite Concretion)

Quartz / Common Opal

Silicon Dioxide (SiO2)

Pea Gravel / River Gravel

Unconsolidated Clastic Sedimentary Aggregate

Labradorite rough fragment

(Ca,Na)[Al,Si]A̲₁O₈

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Crushed Limestone Aggregate

Limestone (Calcium Carbonate, CaCO3)

Gneiss

Gneiss

Quartz (Milky or Clear Quartz fragment)

Silicon Dioxide (SiO2)

Limonitic Sandstone with Inclusion

Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)