Sedimentary Or Igneous Fragment

Weathered quartz-rich stone, possibly chalcedony or calcite

Likely microcrystalline quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Likely weathered quartz-rich stone

Probably quartz-bearing sandstone or milky quartz; exact identification requires testing

Possible weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic rock; likely quartz-rich sandstone with iron-oxide cement

Fossiliferous Limestone with Crinoid Stem

Sedimentary Rock with Echinodermata fossil fragment

Green Fluorite

Calcium Fluoride (CaF2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz)

Silicon Dioxide (SiO2)

Conglomerate (pebble-to-cobble gravel)

Polymictic conglomerate; clast-supported conglomerate in a sandy or silty matrix

Fossilized coral or stromatoporoid fragment

Tabulate coral (e.g., Favosites) or stromatoporoid; exact identification requires microscopy

Metallic sulfide mineral specimen, likely pyrite-bearing ore

Likely pyrite (FeS₂), possibly mixed with other sulfides or host rock

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Fossil shell fragment, likely brachiopod or bivalve

Indeterminate fossilized marine mollusk or brachiopod; mineralized calcite shell in a carbonate matrix

Uncertain coarse-grained igneous fragment

Likely granite or granitic pegmatite; quartz–feldspar–mica assemblage

Clear Quartz

Silicon Dioxide (SiO2)

Quartz Pebble (on Granite)

Silicon Dioxide (SiO2)

Clear quartz

Quartz (silicon dioxide, SiO₂)

Granite Sand (Decomposed Granite)

Grus / Quartz-Feldspar Detritus

Basalt Fragment

Extrusive Igneous Rock

Clear Quartz

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartz-rich rock fragment

Likely granitic or granodioritic rock, composed chiefly of quartz and feldspar with possible mica

Small quartz-rich rock fragment (possibly weathered quartz vein material)

Quartz (SiO₂) in an undetermined host rock; the image is insufficient to identify the host confidently

Small weathered rock fragment, possibly quartz-rich

Unidentified lithic fragment; species cannot be determined from the image

Jasper

Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)

Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Tumbled translucent quartz or chalcedony fragment

Silicon dioxide, SiO₂; likely quartz/chalcedony

Quartz

Silicon Dioxide (SiO2)

Small pale stone, possibly quartz or limestone

Indeterminate from image; likely quartz (SiO₂) or calcite-rich limestone (CaCO₃)

Chert (Flint)

Cryptocrystalline Quartz (SiO2)

White tumbled stone, likely quartz or calcite

Indeterminate; possibly quartz (SiO₂) or calcite (CaCO₃)

Greenstone / Metagraywacke

Metamorphosed basaltic or sedimentary rock (Complex Silicate)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Rosy/Clear variety)

Silicon Dioxide (SiO2)

Calcite

Calcite (calcium carbonate, CaCO₃), likely a massive crystalline specimen

Amethyst

Amethyst (SiO2 - Silicon Dioxide with iron impurities)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially altered granite

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Raw quartz-bearing mineral fragment

Quartz, silicon dioxide (SiO₂), possibly included or matrix-bearing

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Concrete fragment or Conglomerate

Artificial Conglomerate (Concrete) or Natural Conglomerate