Not A Natural Rock (Man Made Composite)

Sandstone (Ferruginous)

Arenite (Fe-rich SiO2)

Ventifact

Eolian Ventifact (often composed of basalt, chert, or quartzite)

Citrine Quartz

Citrine (Silicon Dioxide - SiO2)

Sandstone

Arenite (SiO2 based)

Yellow Quartz (Citrine-colored Quartz Pebble)

Silicon Dioxide (SiO2)

Granite

Granite (Felsic Plutonic Rock)

Granite

Granite (Phaneritic intrusive igneous rock)

Smoky Quartz (with possible Feldspar inclusions)

Silicon Dioxide (SiO2)

Basalt (River Pebble)

Extrusive Mafic Igneous Rock

Banded Agate (specifically Botswana Agate or Water-line Agate)

Chalcedony (cryptocrystalline variety of Quartz), SiO2

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Giallo Ornamental Granite

Phaneritic Igneous Rock (composed of Quartz, Feldspar, and Mica)

Smoky Quartz (Tumbled)

Smoky Quartz (SiO2 - Silicon Dioxide)

Smoky Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (Siliclastic sedimentary rock, primarily SiO2)

Dragon Vein Agate

Silicon Dioxide (SiO2)

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Chalk

CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock

Grey River Pebble (Likely Quartz-rich or Limestone)

Clastic Sedimentary Rock (typically SiO2 or CaCO3 based)

Granite Cobble

Phaneritic Felsic Igneous Rock

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Rough Amethyst

Silicon Dioxide (SiO2) with Iron impurities

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Granite

Granite (Felsic Plutonic Rock)

Sandstone

Arenite (Sedimentary rock composed of sand-sized grains, primarily SiO2)

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2) with iron oxide inclusions

Metallic Ornament / Jewelry

N/A - This is an artificial object, not a geological specimen.

Quartz Crystal (specifically a Double-Terminated variety)

Silicon Dioxide (SiO2) - Low Quartz

Shale (with Iron Oxide staining)

Fissile Mudstone (primarily Quartz and Clay minerals)

Sandstone (likely Quartzose)

Arenite (primarily SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Yellow Quartz (Citrine or Iron-Stained Quartz)

Silicon Dioxide (SiO2)

Smoky Quartz (Tumbled)

Silicon Dioxide (SiO2)

Basalt with Scoria/Vesicular Texture

Vesicular Basalt (Iron-rich/Oxidized)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Shale

Shale (Sedimentary rock composed of mud/clay minerals)

Green Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Shale or Argillite

Shale (sedimentary) / Argillite (metamorphic)

Smoky Quartz in Matrix

Silicon dioxide (SiO2) within Pegmatite/Gneiss

Agate (specifically Botswana or Banded Agate variety)

Chalcedony (Silicon Dioxide, SiO2)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Granitoid (Granite/Granodiorite)

Plutonic igneous rock (variable composition, primarily SiO2)