Unknown (Likely Sedimentary Or Metamorphic)

Magnetite-rich ironstone

Magnetite, Fe₃O₄, likely in a dense ironstone matrix

Weathered quartz-rich rock, possibly quartzite or chert

Quartz (SiO₂), likely in a quartzite matrix; exact identification is uncertain from the image

Dark foliated metamorphic rock, likely schist

Mica schist, probably muscovite–biotite schist

Rounded quartz pebble (tentative)

Quartz, silicon dioxide (SiO₂)

Likely polished gray quartzite or chert

Quartzite, predominantly microcrystalline SiO₂; possibly gray chert (chalcedony/quartz)

Weathered red-and-green metamorphic rock

Probable epidote-amphibolite or altered schist; exact identification requires testing

Tumbled quartz-rich stone, likely marble or calcite

Calcite (CaCO₃), possibly marble

Polished banded gneiss

Biotite–quartz–feldspar gneiss, locally migmatitic

Weathered quartz-bearing metamorphic rock

Likely quartz–feldspar schist or gneiss, possibly with iron-oxide alteration

Gneiss (specifically Pink Gneiss)

Gneiss (high-grade regional metamorphic rock)

Likely biotite-rich schist with a quartz/feldspar inclusion

Mica schist; chiefly quartz (SiO₂), feldspar, and biotite mica

Banded calcite (banded limestone/marble fragment)

Calcite, CaCO₃; likely banded calcitic marble or recrystallized limestone

Assorted polished river pebbles

Mixed lithologies, likely quartzite, chert, jasper, and weathered igneous/metamorphic rocks

Rounded sandstone or quartzite pebble

Indeterminate; likely quartz-rich sandstone (SiO₂-dominated)

Muscovite mica schist

Muscovite-rich schist; predominantly muscovite mica (KAl₂(AlSi₃O₁₀)(OH)₂) with quartz and minor iron oxides

Weathered iron-rich sandstone or lateritic rock

Ferruginous sandstone/laterite; chiefly quartz (SiO₂) with iron oxides such as hematite and goethite

Jasper (Red Jasper)

Silicon Dioxide (SiO2) with Hematite inclusions

Banded gneiss

Quartzo-feldspathic gneiss, likely biotite-bearing

Weathered quartz-rich metamorphic rock

Likely quartzite or quartz-rich gneiss; exact identification requires a fresh surface and testing

Biotite-rich schist (probable mica schist)

Mica schist, dominated by biotite and quartz; possible garnet-bearing variety

Polished hematite (speculative)

Hematite, α-Fe₂O₃; possibly hematite-rich ironstone

Rough blue calcite

Calcite (CaCO₃), likely blue calcite

Polished brecciated jasper

Microcrystalline quartz (SiO₂), commonly with iron oxides and altered volcanic fragments

Tumbled yellow-brown quartzite or jasper

Quartzite, predominantly microcrystalline quartz (SiO₂), possibly iron-stained jasper

Banded gneiss pebble

Gneiss, likely quartz–feldspar–mica gneiss

Tumbled pyrite (likely)

Pyrite, FeS₂; possibly a pyrite-rich sulfide specimen

Sandstone, Quartzite, and River Pebbles

Silicon Dioxide (SiO2) based Sedimentary/Metamorphic structures

Quartzite

Quartzite (containing SiO2)

Gneiss (likely garnet-bearing)

Banded orthogneiss/paragneiss; chiefly quartz, feldspar, biotite and amphibole, with possible garnet

Blue-gray quartz-bearing metamorphic rock (likely gneiss or schist)

Quartz–feldspar–mica rock; exact identification requires testing

Graphite-rich schist (likely graphite ore)

Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar

Polished black stone, likely hematite or black tourmaline

Hematite (Fe₂O₃) or schorl tourmaline (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Light-colored quartz-rich pebble

Likely quartz (silicon dioxide, SiO₂), possibly a weathered quartzite fragment

Mixed tumbled stones

Mixed aggregate of quartz, chalcedony, jasper, feldspar, and other common silicate minerals

Quartz Pebble

Silicon Dioxide (SiO2)

Clear calcite cleavage fragment

Calcite (calcium carbonate, CaCO₃)

Quartz-veined metamorphic cobble

Likely quartzite or quartz-rich metasedimentary rock; veins predominantly quartz (SiO₂)

Weathered quartz-rich rock, possibly chert or quartzite

Likely microcrystalline quartz (SiO₂), but exact identification is uncertain from the photograph

Tumbled banded gneiss

Quartz–feldspar–mica gneiss

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone

Orbicular jasper (likely ocean or leopard jasper)

Siliceous microcrystalline quartz aggregate; mainly SiO₂ with iron oxides and accessory feldspar/carbonates

Tumbled white quartz

Quartz (silicon dioxide, SiO₂)