Not A Rock (Synthetic Material)

Sandstone

Arenite (primarily SiO2)

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of chalcedony (SiO₂), with iron-oxide staining

Sandstone (with potentially high Feldspar/Arkose content)

Clastic sedimentary rock (SiO2 dominated)

Fossilized Shell Impression / Siltstone Fossil

Bivalvia / Brachiopoda mold in Siltstone

Tumbled turquoise

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Weathered gray stone, possibly basalt or granitic rock

Indeterminate fine- to medium-grained silicate rock; possible basalt, diabase, or weathered granite

Tumbled leopard-skin jasper (probable)

Orbicular rhyolite/jasper; primarily microcrystalline quartz (SiO₂) with feldspar and iron-oxide inclusions

Weathered granite or granitic gneiss fragment

Granite; predominantly quartz, feldspar, and mica (exact identification requires testing)

Sandstone

Arenite (SiO2 with various cementing minerals)

Sandstone Pebble

Sandstone (primarily SiO2)

Quartz Pebble with Drusy/Crystalline Pocket

Silicon Dioxide (SiO2)

Polished dendritic agate or jasper pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide inclusions

Sandstone

Arenite

Borosilicate Glass (Manufactured)

SiO2 + B2O3 (Silicon dioxide and Boron trioxide)

Goldstone (Red/Brown)

Aventurine Glass (SiO2 with Copper inclusions)

Quartzite with inclusions

Quartzite

River Pebble (likely Quartzite or Siltstone)

Sedimentary Clast (SiO2 based)

Lapis Lazuli

Lapis Lazuli (a rock composed primarily of Lazurite (Na,Ca)₈[(S,Cl,SO₄,OH)₂|(Al₆Si₆O₂₄)], with varying amounts of Calcite, Pyrite, and Sodalite.)

N/A - Image is non-geological

Acrylonitrile Butadiene Styrene (ABS) or Polypropylene (PP)

Schist

N/A (a rock type, not a mineral formula)

Colorless faceted gemstone, likely synthetic cubic zirconia

Cubic zirconia (zirconium dioxide, ZrO₂); natural diamond is a less likely alternative

Banded sedimentary rock (likely sandstone or siltstone)

Layered siliciclastic sedimentary rock; exact identification is not possible from the image alone

Quartz vein in Schist

Crystalline Silicon Dioxide (SiO2) in Metamorphic Host

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 oxides)

Granite Cobble

Granite

Red Sandstone

Sandstone (principally Quartz, SiO2, with Iron Oxide hematite cement)

Red Sandstone

Sandstone (hematitic/iron-rich quartzite or arenite)

Quartz-veined weathered host rock

Quartz (SiO₂) in a likely altered limestone or metamorphic carbonate host

Limestone and Quartz Gravel with Petrified Wood

Sedimentary gravel aggregate and fossilized wood

Red jasper-like chalcedony pebble

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper

Weathered iron-rich rock, possibly jasper or ironstone

Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests

Clear faceted quartz-like gemstone

Probably rock crystal quartz (SiO₂), though the image may show synthetic glass or cubic zirconia

Unidentified gravel and stone fragments

Mixed, indeterminate lithologies; likely quartz, feldspar, and weathered silicate rock fragments

Conglomerate

Conglomerate Rock

Pink Granite

Phaneritic Plutonic Igneous Rock (high K-feldspar)

Iron-rich breccia or weathered ironstone

Goethite–hematite-bearing limonite, possibly with quartz and altered rock fragments

Sandstone

Sandstone (SiO2-rich clastic sedimentary rock)

Weathered greenish rock fragment

Tentatively altered basalt or serpentinite; exact identification requires testing

Popcorn

Zea mays everta (P. Wilson) (Botanical name for the corn variety)

Painted Sandstone

Sandstone (clastic sedimentary rock) with acrylic/artistic coating

Milky Quartz

Quartz (Silicon Dioxide, SiO2)