Mineral, Part Of A Rock

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Granite with Epidote

Granite, containing quartz, feldspar, and epidote

Moonstone

Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8

Quartz (Druzy on Matrix)

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2) within a geode

Quartz in Matrix (possibly Basalt or Siltstone host)

Silicon Dioxide (SiO2) in Host Rock

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Sandstone

Arenite

Banded Sandstone

Arenite (with iron oxide banding)

Quartz (Milky/Crystalline)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Siliclastic Sedimentary Rock)

Sandstone with Quarzite clasts

Arenite (SiO2 based)

Sandstone (Weathered Cobble)

Clastic sedimentary rock (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.

Shale

Shale (clastic sedimentary rock)

N/A (Non-Geological Specimen)

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Biotite (Black Mica)

Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2

Peach Moonstone

Potassium Aluminum Silicate (KAlSi3O8)

Calcite (Yellow/Orange variety - sometimes called Honey Calcite)

Calcite

Ferruginous Sandstone (Ironstone)

Arenite with Limonite/Goethite cement

Geode (Unopened)

Siliceous Geode (SiO2)

Sandstone

Arenite (primarily SiO2)

Calcite

Calcite (CaCO3)

Basalt with Iron Oxidation (Lattice/Veined)

Mafic Volcanic Rock (principally Plagioclase and Pyroxene)

Bauxite (Laterite Clay)

Bauxite (mixture of Hydrous Aluminum Oxides: Gibbsite Al(OH)3, Boehmite and Diaspore AlO(OH))

Conglomerate

Conglomerate (a clastic sedimentary rock)

Druzy Quartz on Chalcedony Matrix

Silicon Dioxide (SiO2)

Druzy Quartz on Host Rock

Silicon Dioxide (SiO2)

Sandstone with Quartz Vein

Arenite with SiO2 intrusion

Green Aventurine

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

Agate (Common Chalcedony)

Silicon Dioxide (SiO2)

Sandstone (Painted)

Arenite (primarily SiO2)

Sandstone (lithic wacke)

Arenite / Lithic Wacke (mostly SiO2 with rock fragments)

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Basalt with Quartz Vein

Mafic Igneous Rock (SiO2 filling)

Slickenside

Tectonic Fault Scarp Surface

Sandstone (Graywacke)

Clastic Sedimentary Rock (Lithic Sandstone)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Quartz on Matrix

Silicon Dioxide (SiO2)