Sedimentary Rock (Possibly Composed Of Various Minerals)

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Sandstone

Arenite (Siliclastic sedimentary rock), SiO2 + various minerals

Chalcedony or Chert/Jasper with secondary mineral staining

SiO2 (for chalcedony/quartz) with possible secondary copper minerals (e.g., CuSiO3·nH2O for chrysocolla, Cu2(CO3)(OH)2 for malachite) or iron oxides/hydroxides.

Veined Pebble (likely a Quartz-Veined Pebble)

Pebble with Mineral Vein (e.g., Quartz Vein in a Chert/Mudstone Pebble)

Laterite (iron-rich nodule, possibly Bauxite as a subtype)

Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Limonite/Goethite on Shale

Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Pebble

Clast (specifically a granule or small pebble)

Quartz (likely) or a Quartzite Pebble

Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.

Quartz / Common Agate

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone with trace fossil

Sandstone, possibly with Skolithos or similar trace fossil

Quartz (variety of colors)

SiO2 (Silicon Dioxide)

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

Sandstone

Clastic Sedimentary Rock (composed primarily of Quartz: SiO2)

Not a geological specimen

N/A (man-made object)

Shale (possibly)

Shale (fine-grained clastic sedimentary rock)

Bauxite

Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)

Sandstone (likely Graywacke or Lithic Sandstone)

Clastic Sedimentary Rock

Sandstone

Arenite (SiO2 based with various mineral cements)

Sandstone

Arenite (primarily SiO2)

Banded Rock (likely Quartz-rich)

Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals

Pebble or Cobble (likely composed of sandstone or conglomerate)

Clastic Sedimentary Rock (specific name like sandstone, conglomerate, or breccia would require microscopic analysis of clast size and angularity)

Sandstone

Arenite (SiO2 + various cementing minerals)

Sandstone

Arenite (primarily SiO2)

Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.

As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.

Sandstone (Pebble/Conglomerate fragment)

Sandstone (clastic sedimentary rock)

Sandstone

Arenite

Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (primarily SiO2)

Not a rock, mineral, or geological specimen

Metal Chain (Likely Steel or a Steel Alloy)

Steel (primarily iron and carbon); specific alloy unknown

Sandstone

Arenite (composed primarily of SiO2)

Quartz (Float/Abraded)

Quartz (SiO₂)

Bauxite

Bauxite (Al(OH)3, AlO(OH))

Unidentifiable Rock Fragment

Sandstone (likely Quartzose)

Sandstone (Principally SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based)