Unknown (Likely Sedimentary Or Metamorphic)

Banded metamorphic rock, likely gneiss or banded amphibolite

Quartz–feldspar–biotite gneiss or amphibolite; exact identification requires thin-section or mineral tests

Hematite (likely Botryoidal or Specularite variant)

Iron(III) oxide (Fe2O3)

Banded gneiss (likely biotite-bearing)

Gneiss; quartz–feldspar–mica assemblage, with possible iron-oxide staining

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.

Quartz-rich river pebble, likely milky quartz

Milky quartz (SiO₂), possibly a quartzite or quartz-rich silicate pebble

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Likely weathered limestone or marble fragment

Calcite-rich carbonate rock; likely limestone (CaCO₃), possibly recrystallized marble

Tumbled quartz-rich pebble, likely quartzite or chert

Quartz (SiO₂), possibly quartzite; exact identification is uncertain from the image

Felsic Drill Core (likely Gneiss or Granite)

Felsic Metamorphic Rock (Gneissic profile)

Feldspathic Gneiss

High-grade Metamorphic Rock (Gneiss)

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Small pale stone, likely quartzite or limestone fragment

Indeterminate; possible quartzite (mostly SiO₂) or calcitic limestone (CaCO₃)

Banded sandstone or quartzite fragment

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Blue apatite (likely dyed or enhanced)

Apatite group; fluorapatite, Ca5(PO4)3F, is the common blue variety

Quartz geode or quartz-bearing rock

Quartz (SiO₂), likely in a chalcedony- or basalt-hosted cavity

Milky quartz-bearing rock, likely quartzite or silicified limestone

Quartz (SiO₂), possibly in a quartzite or chalcedony-rich matrix

Possible shale or slate fragment

Fine-grained clay-rich rock; possibly slate (low-grade metamorphosed shale)

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Small rounded pebble, likely quartz-rich river stone

Indeterminate; likely quartz/chert-bearing lithic clast

Gray foliated metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface and testing

Quartz-bearing metamorphic rock, likely schist or quartzite

Quartz (SiO₂) in a mica-rich metamorphic matrix

Pyrite (likely)

Iron disulfide, FeS₂; commonly called fool’s gold

Red aventurine quartzite (likely)

Quartzite; predominantly microcrystalline quartz (SiO₂) with iron-oxide and feldspar impurities

Likely weathered limestone or calcitic marble

Calcite-rich carbonate rock; chiefly calcium carbonate, CaCO₃

Banded River Cobble with Mafic Dike

Hydrothermally altered Graywacke or Sandstone with Mafic Intrusion

Limonite (Iron Ore)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Fossilized bivalve shell or shell-rich limestone

Likely an indeterminate fossil mollusk; calcite/aragonite (CaCO₃), possibly preserved in limestone

Likely foliated metamorphic rock (schist or gneiss fragment)

Mica schist–gneiss; chiefly quartz, feldspar, and mica

Clear quartz fragment

Quartz (silicon dioxide, SiO₂)

Likely weathered sandstone or metasandstone

Quartz-rich sandstone (possibly weakly metamorphosed metasandstone)

Dark metamorphic pebble, likely slate or phyllite

Slate/phyllite; chiefly fine-grained mica and quartz, with possible chlorite and graphite

Dark metamorphic rock, likely biotite schist or gneiss

Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing

Fossiliferous limestone (likely crinoidal or shell limestone)

Calcite-rich limestone; predominantly CaCO₃, with visible fossil fragments

Likely gray sandstone or fine-grained metamorphic rock

Quartz-rich lithic sandstone; exact identification is uncertain from the photograph

Biotite-bearing schist

Mica schist, chiefly quartz–feldspar–biotite (phyllosilicate-rich)

Quartz crystal-bearing rock

Quartz (SiO₂), likely a milky/clear quartz vein specimen

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Quartz (Tumbled/Water-worn)

Silicon Dioxide (SiO2)

Garnet

Almandine (Fe3Al2(SiO4)3)

Likely foliated metamorphic rock, possibly schist

Mica schist or micaceous quartzite; exact identification is uncertain from the photograph

Amethyst and mixed gemstone bracelet

Amethyst: purple quartz, silicon dioxide (SiO₂); likely accompanied by other quartz or decorative mineral beads

Rounded gray metamorphic pebble, likely gneiss or granitic rock

Probable quartz–feldspar–mica gneiss; exact identification requires a fresh surface and testing