Sedimentary And Metamorphic

Muscovite

Muscovite (KAl2(AlSi3O10)(OH)2)

Magnetite

Magnetite (Fe3O4)

Fuchsite

K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)

Mica in Quartz Host

Muscovite (KAl2(AlSi3O10)(OH)2) in Quartz (SiO2)

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

Muscovite Mica

Muscovite: KAl2(AlSi3O10)(OH)2

Rhodonite

Rhodonite (Manganese silicate), (Mn,Fe,Mg,Ca)SiO3

Zoisite with Ruby

Anyolite (Ca2Al3(SiO4)3(OH) with Al2O3:Cr)

Nephrite Jade

Ca2(Mg, Fe)5Si8O22(OH)2

Blue Sapphire

Corundum (Al2O3)

Quartzite (River-worn Shiner)

Quartzite (Formula: SiO2)

Unakite (Epidotized Granite)

Unakite; primarily composed of Epidote (Ca2(Al,Fe)3(SiO4)3(OH)), Orthoclase (KAlSi3O8), and Quartz (SiO2)

Schist

Mica Schist (predominantly Muscovite or Biotite)

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

Greenschist

Chlorite schist

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.

Greenschist / Chloritaform Schist

Chlorite Schist (Group of Silicate Minerals)

Biotite (Black Mica)

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

Quartzite

Quartzite (primarily SiO2)

Quartzite pebble

Quartzite (SiO2)

Epidote in Matrix (Unakite-related)

Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Marble

Metamorphic rock composed of Recrystallized Carbonate Minerals (chiefly CaCO3)

Fuchsite Gneiss (Green Quartzite)

Chromium-rich Muscovite (KAl2(AlSi3O10)(OH)2 with Cr replacements)

River Quartzite (or Quartz Cobble)

Quartzite (primarily Silicon Dioxide - SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Pink Quartz (Rose Quartz variant)

Silicon Dioxide (SiO2)

Gossan (Iron Hat)

Limonitic Gossan (Fe-oxide/hydroxide complex)

Quartzite

Quartzite (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartzite Cobble

Quartzite (primarily SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (SiO2)

Cream Marble (Speckled)

Metamorphosed Limestone (mainly CaCO3)

Unakite

Epidotized Granite

Schist (specifically Mica Schist)

Mica Schist

Quartz (Milky/Crystalline)

Silicon Dioxide (SiO2)

Dragon Stone (Dragon Blood Jasper)

Epidote with Pietersite or Red Jasper inclusions (varied SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))

Nephrite Jade

Ca2(Mg,Fe)5Si8O22(OH)2

Yellow Quartzite

Quartzite (primarily SiO2)

Garnet-Bearing Schist

Almandine Garnet Micaceous Schist