Rock (Likely Sedimentary)

Dark mica-rich metamorphic rock, likely schist

Mica schist, probably biotite–muscovite schist; exact identification requires testing

Blue Chalcedony

Chalcedony (Silicon Dioxide, SiO2)

Quartz vein in host rock

Quartz (SiO₂), likely in a weathered carbonate or sedimentary matrix

Garnet (Almandine)

Almandine, Fe3Al2(SiO4)3

Mixed tumbled gravel and quartz-rich sandstone

Primarily quartz (SiO₂), feldspar, and lithic sedimentary fragments; one piece appears to be quartz-rich sandstone

Sandstone (likely Quartzose Sandstone)

Clastic Sedimentary Rock (primarily SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded gneiss (likely biotite-bearing)

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

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (composed mostly of SiO2)

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Limestone (likely weathered)

Limestone (Mainly Calcium Carbonate, CaCO3)

Weathered sandstone or iron-stained limestone

Likely quartz-rich sandstone (SiO₂) or ferruginous limestone (CaCO₃); exact identification requires testing

Weathered sandstone fragment

Quartz-rich sandstone, likely ferruginous sandstone

Blue-gray quartz-bearing rock, likely rough chalcedony or silicified host rock

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining and minor feldspar/clay minerals

Foliated metamorphic cobble, likely gneiss

Biotite–quartz–feldspar gneiss (tentative)

Fossilized Brachiopod

Phylum Brachiopoda (likely Order Spiriferida or Orthida)

Chert (Quartz Variety)

Microcrystalline / Cryptocrystalline Quartz (SiO2)

Rounded beach pebble

Lithology indeterminate; likely fine-grained sandstone, mudstone, or weathered volcanic rock

Rounded conglomeratic river pebble

Polymict conglomerate (lithified gravel), composition uncertain from image

Weathered River Rock (likely Chert or Basalt with algae)

Silicon dioxide (SiO2) with organic biofilm

Chert or flint fragment

Microcrystalline quartz (SiO₂), likely silicified rock

Weathered sandstone or iron-rich sedimentary rock fragments

Quartz-rich sandstone, locally ferruginous; exact identification requires testing

Chert (or Fossiliferous Limestone)

Microcrystalline Quartz (SiO2) / Calcium Carbonate (CaCO3)

Chert Pebble

Microcrystalline quartz (SiO2)

Sandstone (likely Ferruginous)

Arenite with Iron Oxide cement

Fossiliferous limestone

Calcitic limestone, primarily calcium carbonate (CaCO₃), with visible shell or coral fossils

Weathered rock pebble, possibly quartz-rich sandstone

Uncertain from the image; likely quartz-bearing sandstone with iron-oxide staining

Weathered chert or siliceous limestone

Microcrystalline quartz (SiO₂), possibly with carbonate minerals

Coarse-grained metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (tentative; exact identification requires testing)

Unknown Rock Specimen

Vein-bearing sandstone or quartzite cobble

Quartz-rich sandstone with white quartz veins; possibly metamorphosed to quartzite

Likely weathered quartz-rich rock fragments

Uncertain; visually consistent with massive quartz or quartz-bearing sandstone

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Weathered quartz-rich metamorphic rock

Likely quartzite or quartz-veined schist; primarily SiO₂ with possible mica, feldspar, and iron oxides

Yellow Quartz (Chalcedony or Agate)

Silicon Dioxide (SiO2)

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Mixed rough mineral specimens, likely calcite with prehnite/zeolite

Calcite (CaCO₃), with probable prehnite (Ca₂Al₂Si₃O₁₀(OH)₂) and/or zeolite-group minerals

Gneiss

Feldspar–quartz–mica gneiss, locally amphibole-bearing

Likely weathered granite or granitic gneiss fragments

Granite: quartz–feldspar–mica aggregate; possibly biotite granite or weakly foliated gneiss

Weathered sandstone or iron-stained quartzite pebble

Likely quartz-rich sandstone (mostly SiO₂), possibly weakly metamorphosed quartzite

Weathered gray metamorphic rock, likely slate or phyllite

Foliated metapelite; composition commonly quartz, mica, and chlorite

Likely assorted beach/river pebbles

Undetermined mixed lithologies; visible pieces may include quartz-rich and volcanic rocks