Industrial Byproduct (Often Confused With Igneous Rocks Or Meteorites)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Stilbite

Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O)

Gneiss (Metamorphic Cobble)

Gneiss (High-grade Regional Metamorphic Rock)

White Agate (Chalcedony)

Agate (Silicon Dioxide - SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Granite

Granite

Banded Gneiss with Quartz Vein

Foliated Metamorphic Rock (Gneiss)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Amazonite

K(AlSi3O8) - Lead-bearing Microcline (Tectosilicate)

Astrophyllite

Potassium Sodium Iron Manganese Titanium Silicate Hydroxide (K3NaFe7Ti2Si8O24(OH)7)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz Geode/Cluster

Quartz (SiO2)

Basalt

Vesicular Basalt

Quartz Pebble

Silicon Dioxide (SiO2)

Sodalite

Na8(Al6Si6O24)Cl2 (Sodium Aluminum Silicate Chloride)

Scoria

Vesicular Basalt / Scoria (Mafic silicate rock)

Granite

Granite (a plutonic igneous rock composed primarily of quartz and feldspar)

Yellow Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Pyrite (or Fool's Gold)

Pyrite (FeS₂)

Gneiss

Gneiss

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.

Black Chert

Chert (microcrystalline quartz)

Talc

Talc (Mg₃Si₄O₁₀(OH)₂)

Quartz nodule (River pebble)

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Amygdaloidal Basalt with Epidote

Vesicular Basalt with secondary Epidote/Quartz mineral infill

Granite (with Almandine Garnet inclusions)

Granite composed primarily of Quartz (SiO2), K-Feldspar (KAlSi3O8), and Almandine Garnet (Fe3Al2(SiO4)3)

Carnelian

Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)

Labradorite

Labradorite (Plagioclase Feldspar Series: (Ca,Na)(Al,Si)4O8)

Coarse-grained Quartz with Feldspar inclusions

Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions

Quartz Pebble (Iron-Stained)

Silicon Dioxide (SiO2)

Quartz (Milky or Rough Quartz)

Silicon Dioxide (SiO2)

Carnelian

Carnelian (SiO2, Silicon Dioxide with Iron Oxide impurities)

Pyrite

Iron Disulfide (FeS2)

Galena

Lead Sulfide (PbS)

Quartz (likely milky quartz or a stained variety)

Silicon Dioxide (SiO₂)

Opal

Hydrous silicon dioxide (SiO2·nH2O)