Rock (Likely Sedimentary)

Chert on Volcanic Host Rock

Sedimentary Chert (SiO2) within Basalt or Andesite

Chert (variably called Jasper or Agate)

Microcrystalline Quartz (SiO2)

Jasper (likely Iron-stained)

Silicon Dioxide (SiO2) with iron oxide inclusions

Rounded sedimentary pebble, likely limestone or calcareous sandstone

Indeterminate carbonate-rich clastic rock; possibly micritic limestone (predominantly CaCO₃)

Weathered breccia or conglomeratic sandstone

Clastic sedimentary rock, likely carbonate-cemented breccia/conglomerate

Banded quartz-rich metamorphic rock (likely quartzite or quartz-mica schist)

Quartzite/schist composed chiefly of SiO₂ quartz with mica, feldspar, and iron-oxide or copper-colored accessory minerals

Gneiss

Gneiss

Weathered stone, likely sandstone or altered volcanic rock

Indeterminate; possibly quartz-rich sandstone or weathered tuff

River Pebble (Gneiss or Quartzite variant)

Metamorphic rock specimen (likely Quartzite or Gneiss)

Likely weathered brown rock fragment

Indeterminate; possibly iron-oxide-stained sandstone or laterite

Iron-rich sandstone or weathered laterite fragment

Quartz-rich sandstone, possibly ferruginous sandstone (SiO₂ with iron oxides such as hematite/goethite)

Banded chert or agate pebble

Microcrystalline quartz (SiO₂), likely chalcedony/chert

Chert Nodules with Iron Staining

Microcrystalline Quartz (SiO2)

Sandstone (River Cobble)

Clastic sedimentary rock (primarily SiO2 with various lithic fragments)

Likely reddish granite/porphyritic igneous rock fragments

Feldspar–quartz–mica aggregate, possibly pink granite or rhyolite

Rounded brown river pebble

Likely weathered sandstone or iron-stained quartz-rich rock; exact identification requires testing

Milky quartz-bearing rock, likely quartzite or silicified limestone

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

Quartz-rich rock fragment

Milky quartz, primarily silicon dioxide (SiO₂), possibly quartzite or a feldspar-bearing vein rock

Unidentified small rock fragment

Indeterminate; appearance may be consistent with a weathered sandstone or limestone fragment

Quartzite with Chert inclusions

Metamorphosed Quartz-rich Rock (SiO2)

Greenish Metamorphic Rock (likely containing epidote or chlorite)

Metamorphic rock, possibly epidosite or greenstone

Iron-rich weathered rock, possibly limonite-bearing sandstone or laterite

Goethite–hematite/limonite assemblage, likely in a ferruginous sandstone or weathered host rock

Weathered chert or silicified limestone nodule

Microcrystalline quartz (SiO₂), possibly replacing limestone; exact identification requires testing

Likely graywacke or fine-grained metamorphic rock

Quartz–feldspar–mica-rich lithic sandstone (tentative; image alone is insufficient for exact identification)

Rounded river pebble, likely weathered limestone or sandstone

Indeterminate carbonate or siliciclastic sedimentary rock; likely limestone (calcite-rich, CaCO₃) or lithic sandstone

Sandstone (likely Arkosic or Quartzose)

Arenite (SiO2 based with mineral inclusions)

Likely weathered sandstone or iron-stained quartzite fragment

Quartz-rich sandstone (predominantly SiO₂; exact identification uncertain from image)

Weathered quartz-rich rock, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Pink chalcedony / quartz fragment (probable)

Microcrystalline quartz, SiO₂ (likely iron-stained chalcedony or quartzite)

Granite Gneiss with Garnet

Garnetiferous Gneiss

Likely calcite-rich limestone or marble fragment

Calcite (CaCO₃), probably micritic limestone; exact identification requires testing

Pyritic Sandstone

Clastic Sedimentary Rock (Pyrite-bearing Sandstone)

Banded Gneiss

Gneiss (Metamorphic Rock)

Quartz Veined Siltstone

Siltstone with Quartz Intrusion (SiO2)

Quartz-bearing gray rock, likely druzy quartz in host rock

Quartz (SiO₂), possibly in a chert, chalcedony, or fine-grained volcanic host

Weathered gray-green rock fragment

Likely shale or mudstone; exact identification requires testing

Dark metamorphic rock, likely biotite schist or hornblende-bearing gneiss

Probable mica schist/amphibolite; composition may include biotite, amphibole, quartz, feldspar, and iron oxides

Sandstone (likely Graywacke or Siltstone variety)

Clastic Sedimentary Rock (SiO2 with assorted mineral fragments)

Fossilized bivalve shell or shell-rich limestone

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

Weathered calcite-rich limestone fragment

Limestone, predominantly calcite (CaCO₃), possibly bioclastic

Granite Gneiss

Gneiss (High-grade metamorphic rock)

Rounded greenish river pebble

Indeterminate; possibly weathered greenstone, basalt, or serpentinized ultramafic rock