Not A Rock Or Mineral

Small cylindrical mineral/stone fragment

Undetermined; the image is insufficient for reliable mineral identification

Granite

Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)

Orange Quartz (or Carnelian Chalcedony)

Silicon Dioxide (SiO2)

Yellow-brown stone or mineral fragment

Unidentified; the image does not show enough detail for a reliable identification

Granite

Felsic intrusive igneous rock

Sandstone with Secondary Mineral Encrustation

Arenite with Silica/Calcite deposits (SiO2 or CaCO3)

Weathered porphyritic basalt

Basalt, likely plagioclase-phyric basalt; primarily a fine-grained aggregate of plagioclase feldspar, clinopyroxene, and possibly olivine or iron-titanium oxides

Polished orange-and-white agate slice

Banded chalcedony, microcrystalline quartz (SiO₂)

Greenstone (likely chlorite- or epidote-altered basalt)

Metamorphosed mafic volcanic rock; commonly chlorite–epidote–actinolite assemblage

Greenstone (likely chlorite-rich metamorphic rock)

Chlorite-bearing greenschist; exact identification requires testing

Quartz

Silicon Dioxide (SiO2)

Granite

Intrusive igneous rock

Basalt with Quartz/Calcite Veins

Aphanitic Mafic Igneous Rock (Hydrothermal Veined)

Basalt

Basalt

Schist

Schist (Metamorphic Rock)

Chert Pebble

Chert (Microcrystalline Quartz, SiO2)

Rounded pebble with a brown mineral or rock inclusion

Unidentified lithic pebble; the pale matrix and brown patch cannot be identified reliably from the image

Vein Quartz in Limestone

Calcium carbonate with silicon dioxide (CaCO3 + SiO2)

Basalt with Amygdules

Extrusive Igneous Rock

Likely rough garnet crystal

Garnet group, possibly almandine (Fe₃Al₂(SiO₄)₃)

Sandstone (River Cobble)

Clastic sedimentary rock (primarily SiO2)

Basalt (Vesicular or Porphyritic River Pebble)

Mafic Volcanic Rock (Aphanitic to Porphyritic Basalt)

Granite

Phaneritic Felsic Igneous Rock

Dark green-gray river-worn rock, likely serpentinite

Serpentinite (rock composed chiefly of serpentine-group minerals; identification is provisional from the photograph)

Veined Pebble (Quartz/Calcite Veined Metamorphic/Sedimentary Rock)

Quartz / Calcite Veined Fault Breccia or Metamorphic Pebble

Likely rough garnet

Garnet group, possibly almandine (Fe₃Al₂(SiO₄)₃); identification is uncertain from the image

Weathered granite or granitic gneiss

Granite; predominantly quartz, feldspar, and mica (exact identification is uncertain from the image)

Asphalt aggregate pavement

Bituminous asphalt concrete containing crushed stone aggregate

Likely brecciated jasper or iron-stained quartz-rich rock

Jasper-bearing breccia; exact identification requires testing

Sandstone

Clastic sedimentary rock

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

River Stone (Sedimentary Sandstone/Quartzite)

Arenite/Quartzite transition specimen

Banded Sandstone Peabble

Arenite with iron oxide banding

Sandstone with Quarzite clasts

Arenite (SiO2 based)

Wishing Rock (Quartz Vein in Host Rock)

Silicon dioxide (SiO2) vein in various host rocks

Large rounded metamorphic boulder, likely gneiss or granitic gneiss

Gneiss (likely quartz–feldspar–mica gneiss; exact identification requires closer examination)

Granite

Granite; chiefly quartz, feldspar, and mica

Weathered granite fragment

Granite, primarily quartz, feldspar, and mica

Quartz geode

Crystalline quartz (SiO₂), lining a geode cavity

Possible green tumbled stone

Unidentified green mineral or rock; the image is too blurred for reliable identification

Granite

Felsic intrusive igneous rock

Granite

Granite (Intrusive Igneous Rock)