Metamorphic Rock (Formed From A Fibrous Crocidolite Asbestos)

Quartzite

Quartzite (primarily SiO2)

Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Garnet (almandine or pyrope variety)

Silicate mineral Group: (Fe, Mg, Mn, Ca)3(Al, Fe, Cr)2(SiO4)3

Quartzite

Quartzite (primarily SiO2)

Satin Spar (Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Moonstone

Orthoclase Feldspar (composed of alternate layers of orthoclase and albite), (K,Na)AlSi3O8

Quartzite Pebble

Quartzite (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Milky Quartz

Silicon Dioxide (SiO2)

Quartzite River Stone

Quartzite (primarily SiO2)

Quartzite

Quartzite (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartzite

Quartzite (SiO2)

Blue Apatite

Apatite group (Ca5(PO4)3(F,Cl,OH))

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

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.

Gneiss (Metamorphic Rock)

Gneiss

Quartz (in a rock matrix)

Quartz (SiO2)

Quartzite

Quartzite (SiO2 silicon dioxide)

Green Aventurine

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

Quartz

Silicon Dioxide (SiO2)

Yellow Quartzite

Quartzite (SiO2)

Quartzite with Iron Staining

Quartzite (primarily SiO2 with Fe2O3 staining)

Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (SiO2)

Hypersthene (or Enstatite/Ferrosilite)

Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)

Quartzite Pebble

Quartzite (composed primarily of Silica, SiO2)

Quartzite Pebble

Quartzite (primarily SiO2)

Schist

Mica Schist (Medium-grade metamorphic rock)

Gneiss

Gneiss (High-grade metamorphic rock)

Quartz on Greenstone

Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit

Quartzite (Milky Quartz pebble)

Silicon Dioxide (SiO2)

Quartzite / Sandstone / Chert Mix

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss Pebble

Gneiss

Milky Quartz (with Iron Oxide staining)

Quartz (Silicon Dioxide - SiO2)

Garnet (Almandine)

Almandine, Fe3Al2(SiO4)3

Yellow Quartzite (Iron-Stained Quartz)

Quartzite (SiO2 with Fe-oxide impurities)

Blue Sapphire

Corundum (Al2O3) with traces of Iron and Titanium