Mineral Like Byproduct (Often Mistaken For Igneous Rock Or Meteorite)

Aventurine

Aventurine Quartz (SiO2 with inclusions)

Pumice

Pumicite (Amorphous glass with varying chemical composition, often rhyolitic)

Sandstone

Arenite (composed primarily of SiO2)

Red Scoria (Lava Rock)

Scoria (Extrusive Igneous Rock / Mafic composition)

Granite (River-worn Cobble)

Phaneritic Felsic Igneous Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Granite

Phaneritic Igneous Rock (Granite)

Biotite (Mica)

K(Mg,Fe)3AlSi3O10(OH,F)2

Gneiss (Metamorphic Rock)

Gneiss

Granite

Granite (Phaneritic intrusive igneous rock) - Composition: SiO2, Al2O3, K2O, Na2O

Moss Agate

Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Siltstone

Siltstone (composed of clastic quartz and feldspar)

Granite River Rock

Phaneritic Felsic Igneous Rock (Granite)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz (Rock Crystal) with minor impurities

Quartz (SiO2)

Dalmatian Stone

Dalmatian Jasper (Peralkaline Quartz-Feldspar Rock)

Basalt

Basalt (SiO2 percentage between 45% and 52%)

Granite

Granite (a felsic intrusive igneous rock)

Quartz Crystal

Quartz (SiO₂)

Graphite

Graphite (Carbon, C)

Chinese Writing Stone

Porphyritic Basalt or Porphyritic Andesite with Feldspar phenocrysts (SiO2-rich Silicates)

Sandstone

Arenite

Granite

Granite (Felsic Plutonic Rock)

Diorite

Diorite (Intermediate intrusive igneous rock)

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Clear Quartz

Silicon dioxide (SiO2)

Obsidian

Obsidian (principally SiO2)

Blue Apatite

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

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Scoria

Scoria (Vesicular Basalt)

Muscovite Mica

Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))

Quartz (Milky/Smoky variety)

Silicon Dioxide (SiO2)

Sandstone (with potential fossil inclusions)

Clastic sedimentary rock (primarily SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic Plutonic Felsic Igneous Rock (Granite)

Milky Quartz Pebble

Quartz (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.

Flesh-toned Siltstone

Siltstone (composed of microscopic Quartz and Feldspar grains)

Breciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions