This Is Not A Rock Or Mineral

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Banded Gneiss

Gneiss (Felsic to Mafic Metamorphic Rock)

Granite, likely weathered biotite granite

Phaneritic intrusive igneous rock composed chiefly of quartz, feldspar, and biotite amphibole

Quartz (Druzy)

Silicon Dioxide (SiO2)

Conglomeratic gravel / lithified alluvial deposit

Polymictic conglomerate or pebble-rich sandstone (likely weakly cemented)

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Quartz Vein in Hematitic Siltstone

Hydrothermal Quartz (SiO2) in Ferriferous Matrix

Quartz vein in dark host rock

Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock

Weathered iron-rich rock fragment

Likely limonite/goethite with hematite and iron-bearing silicates; exact identification requires testing

Amygdaloidal Basalt

Amygdaloidal Mafic Volcanic Rock

Quartz Vein in Host Rock

Quartz (SiO2) in Mafic or Sedimentary Matrix

Sandstone

Clastic Sedimentary Rock

Unidentified pale stone or mineral specimen

Indeterminate; possibly massive quartz, calcite, or a light-colored feldspathic rock

Red Sandstone

Sedimentary Clastic Rock (Quartz Arenite)

Granite

Phaneritic intrusive igneous rock

Basalt

Aphanitic Mafic Igneous Rock

Granite fragment (tentative)

Granite; primarily quartz (SiO₂), feldspar, and mica

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Black river rock, likely basalt

Basalt (fine-grained mafic volcanic rock; identification from photo is tentative)

Likely garnet (rough crystal)

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

Small rounded pebble, possibly quartz-rich stone

Indeterminate from image; likely quartz-bearing silicate rock

Weathered garnet-bearing gneiss (likely)

Garnet-bearing gneiss; exact mineral identification is uncertain from the photograph

Lichen-covered granite or granitic gneiss

Granite: quartz + feldspar + mica; possibly gneiss if foliation is confirmed

Likely amphibolite

Amphibolite, composed mainly of hornblende (amphibole) and plagioclase feldspar

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Sandstone

Sedimentary Rock (Quartz arenite)

Weathered granitic rock

Granite, likely quartz–feldspar–mica aggregate

Weathered iron-rich rock, likely limonite/goethite-bearing laterite

Limonite–goethite aggregate, commonly approximated as hydrated iron oxides (FeO(OH)·nH₂O)

Chalcedony (Agate/Chert variety)

Silicon Dioxide (SiO2)

Quartz (Druzy)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Fine-grained, banded rock (possibly gneiss)

Unidentified foliated silicate rock; composition cannot be determined from this close-up

Granite

Granite (Phaneritic intrusive igneous rock)

Banded Sedimentary Rock

Stratified Siliciclastic / Arenite or Siltstone with Mineral Bands

Shale

Lutaceous sedimentary rock

Granite

Intrusive Felsic Igneous Rock

Granite Gneiss

Granitic Gneiss

Sandstone (Quartzose)

Arenite (SiO2 based typically)

Serpentinite (often called Jade or Nephrite substitute)

Serpentinite (composed primarily of Antigorite, Lizardite, or Chrysotile)

Wavellite with Quartz

Al3(PO4)2(OH,F)3 & SiO2

Iron-stained quartz (probable quartz vein fragment)

Quartz, SiO₂, with iron-oxide staining

Granite

Intrusive Igneous Rock (Felsic)