Mineral, Specifically A Rock Fragment

Granite Pegmatite

Phaneritic Plutonic Igneous Rock

Quartz Druzy (Geode Fragment)

Silicon Dioxide (SiO2)

Brecciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Small brown mineral/rock fragment (unidentified)

Undetermined from the image; no reliable species identification is possible from appearance alone.

Chert (White Chert / Flint)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Greenstone (likely chlorite-rich metamorphic rock)

Chlorite-bearing greenschist; exact identification requires testing

Sandstone

Clastic Sedimentary Rock

Small dark mineral or rock fragment

Indeterminate; possibly mica-rich schist, biotite, or a dark sulfide mineral

Weathered granite (probable)

Granite; chiefly quartz, feldspar, and minor mica

Pink Granite

Phaneritic Quartz-Feldspar Plutonic Rock

Small metallic-looking rock fragment

Uncertain; possibly galena-bearing ore or mica-rich schist

Likely gray-green metamorphic rock fragment

Unidentified fine-grained metamorphic rock; exact identification is not possible from this small image

Amethyst (Chevron or Banded variety)

Silicon Dioxide with Iron impurities (SiO2)

Iron-rich reddish rock, possibly weathered basalt or ironstone

Indeterminate; likely oxidized mafic rock containing iron oxides and silicate minerals

Polished breccia (decorative stone)

Likely carbonate breccia: angular carbonate-rock fragments in a calcite-rich matrix; exact identification requires testing

Granite Pebble

Granite (composed primarily of Quartz, Feldspar, and Mica)

Red Sandstone

Clastic Sandstone (typically Quartz-rich with Iron Oxide)

Quartz / Common Opal Transition

Silicon Dioxide (SiO2)

Small dark mineral/rock fragment

Indeterminate; possibly magnetite-bearing basalt or iron-rich slag

Small gray rock fragment

Unidentified rock; the image lacks enough detail for reliable mineral identification

Unidentified rounded mineral/rock fragment

Indeterminate; likely a weathered quartz-rich stone or iron-stained granite fragment

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Weathered iron-rich stone, possibly sandstone or ironstone

Indeterminate; likely quartz-rich sandstone with iron-oxide cement, possibly hematite/goethite

Sandstone

Clastic Sedimentary Rock

Red Sandstone

Sedimentary Clastic Rock (Quartz Arenite)

Granite Pebble

Granite (phaneritic igneous rock)

Small brown rock fragment; exact identification uncertain

Unidentified fine-grained lithic fragment

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Shale fragment

Shale (Laminated Mudstone)

Sandstone (with secondary weathering/concretion)

Arenite (composed primarily of Quartz, SiO2)

Basalt fragment

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and commonly olivine

Quartz-bearing rock fragment

Likely quartz (SiO₂) with iron-oxide staining and possible host-rock grains

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.

Pink Granite

Granite (Phaneritic Acidic Igneous Rock)

Green Aventurine

Silicon Dioxide (Quartz) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Agate (specifically Waterline or Onyx-type Agate)

Silicon Dioxide (SiO2) - variety Chalcedony

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and organic impurities

Amygdaloidal Basalt

Amygdaloidal Basalt

Uncertain dark gray-brown rock fragment

Indeterminate; possibly weathered chert, serpentine, or iron-stained quartzite