Metamorphic (Likely Gneiss Or Schist Based On Texture)

Gneiss

Metamorphic Gneiss

Garnet (Almandine or Pyrope)

Garnet group; (Fe,Mg)3Al2(SiO4)3

Biotite Schist

Biotite Schist (containing K(Mg,Fe)3AlSi3O10(OH)2)

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous quartz–feldspar metamorphic rock; exact mineralogy requires testing

Quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂)

River Pebble (Gneiss / Granitic Schist)

Metamorphic Rock (Quartz-Feldspar-Mica assembly)

Banded Gneiss

Gneiss (Metamorphic high-grade rock)

Mica schist

Schist dominated by muscovite/biotite mica, commonly with quartz and feldspar

Dumortierite Quartz

Dumortierite (Al7BO3(SiO4)3O3 / inclusion in SiO2)

Iron-stained weathered rock

Unknown

Banded gneiss cobble

Gneiss, commonly quartz–feldspar–mica gneiss

Dark metamorphic rock, likely biotite schist or hornblende-bearing gneiss

Probable mica schist/amphibolite; composition may include biotite, amphibole, quartz, feldspar, and iron oxides

Schist

Schist (various compositions)

Blue Kyanite

Kyanite (Al2SiO5)

Mica Schist (with Garnet)

Garnet-Mica Schist

Mica Schist with Quartz

Schist containing Muscovite and Quartz

Greenstone (likely altered basalt or serpentinite)

Chlorite-rich metabasalt or serpentinite; exact identification requires testing

Mica Schist

Mica Schist

Aquamarine

Beryl (Be3Al2(SiO3)6)

Biotite-bearing granite or granitic gneiss

Quartz–feldspar granite with biotite and accessory mica/amphibole

Biotite-rich gneiss (probable)

Foliated quartz–feldspar–mica gneiss; composition typically quartz (SiO₂), feldspars, and biotite mica

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Foliated metamorphic rock, likely biotite gneiss or schist

Biotite-rich gneiss/schist; chiefly quartz, feldspar, and biotite mica

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Cordierite (Iolite) in Quartz

Cordierite (Magnesium iron aluminium cyclosilicate) - Mg2Al4Si5O18

Muscovite Schist

Mica Schist (KAl2(AlSi3O10)(OH)2 matrix)

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.

Foliated metamorphic rock, likely schist

Mica schist or chlorite schist; composition commonly quartz + mica/chlorite ± feldspar

Garnet

Garnet Group (formula varies, e.g., Almasndine: Fe3Al2(SiO4)3)

Garnet

Garnet Group (Silicate Minerals), formula varies e.g., Almandine Fe3Al2(SiO4)3

Green Aventurine

Quartz (SiO2) with fuchsite inclusions

Red Garnet

Garnet Group (e.g., Pyrope, Almandine, Spessartine, Grossular, Andradite, Uvarovite)

Dark gray metamorphic rock fragment, likely slate or schist

Fine-grained foliated silicate rock; composition likely quartz, feldspar, mica, and/or chlorite

Iolite (Cordierite)

Cordierite (Magnesium iron aluminum cyclosilicate), Mg2Al4Si5O18

River Cobble (Quartzite or Gneiss)

Metamorphic crystalline rock (predominantly SiO2 based)

Mica-rich schist (likely biotite schist)

Biotite–quartz schist; typically quartz + biotite mica ± feldspar, muscovite, and garnet

White sheet mica (likely muscovite)

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Garnet

Almandine formula: Fe3Al2(SiO4)3

Banded Gneiss

Metamorphic Gneiss

Polished gray stone, likely quartzite or river-worn granite

Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph

Mica Schist

Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3(AlSi3O10)(OH)2)

Quartz–iron oxide-bearing metamorphic rock, possibly garnet schist or gneiss

Quartz, feldspar, mica, and iron oxides; exact identification requires testing