Mineral In Metamorphic Rock

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Granitic Gneiss

Gneiss (containing Potassium Feldspar and Quartz)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Green Aventurine (Gua Sha tool)

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Potassium Feldspar

Orthoclase (KAlSi3O8)

Blue Schist / Lydian Stone / Chert with Glaucophane

Metamorphic rock containing quartz and glaucophane

Iolite-bearing Gneiss (Cordierite)

Cordierite (Mg2Al4Si5O18) in Gneiss matrix

Quartzite

Quartzite (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Quartz Pebble

Silicon Dioxide (SiO2)

Mica Schist with Quartz

Schist containing Muscovite and Quartz

Clear Quartz

Silicon Dioxide (SiO2)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gold-bearing Quartz

Quartz (SiO2) with associated pyrite or native gold

Greenstone

Metamorphic mafic rock (chlorite-actinolite-epidote schist)

Dark weathered igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Greenschist (Chlorite Schist)

Greenschist (containing chlorite, actinolite, and epidote)

Quartzite with Quartz Geode / Vug

Crystalline Silicon Dioxide (SiO2) in Metamorphic Host

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)

Emerald in Matrix

Beryl (Be3Al2Si6O18) with trace amounts of Chromium/Vanadium

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Green Aventurine

Silicon Dioxide (Quartz variety with Fuchsite inclusions - SiO2)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Quartz (Milky/Yellowish)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (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.

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Pyrite (Fools Gold)

Iron Sulfide (FeS2)

Mica Schist

Mica Schist (primarily Muscovite and Biotite KAl2(AlSi3O10)(OH)2)

Gneiss with Quartz/Feldspar Vein

Felsic to intermediate gneiss

Milky quartz

Quartz (SiO₂), commonly massive or vein quartz

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Slate

Metamorphic Pelitic Rock

Slate

Metamorphic Pelitic Rock

Slate

Metamorphic Pelitic Rock

Quartzite

Metamorphic rock (SiO2)

Quartzite

Metamorphic Rock (Quartzite)

Quartzite

Metamorphic rock (SiO2)

Iron-stained Quartzite / Chert

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Blue Sapphire

Corundum (Al2O3) with traces of Iron and Titanium