Mineral (Tectosilicate)

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

Quartz Geode in Sedimentary Matrix

Silicon Dioxide (SiO2) within a limestone/dolostone host

Garnet (Almandine/Pyrope variety)

Silicate mineral group; typically Fe3Al2(SiO4)3 (Almandine) or Mg3Al2(SiO4)3 (Pyrope)

Peridot (likely, based on color and appearance)

Olivine group mineral, specifically (Mg,Fe)2SiO4 (Forsterite-Fayalite solid solution series)

Asphalt (Bituminous pavement fragment)

Artificial conglomerate / Bitumen-Aggregate mixture

Sugilite

Sugilite (KNa2(Fe,Mn,Al)2Li3Si12O30)

Garnet (likely Almandine or Pyrope)

Garnet Group (e.g., Almandine: Fe3Al2(SiO4)3; Pyrope: Mg3Al2(SiO4)3)

Quartz (Milky/Smoky variety on matrix)

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic intrusive igneous rock (Felsic)

Coarse-grained Quartz with Feldspar inclusions

Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions

Foliated Gneiss (River-Worn Pebble)

Gneiss (High-grade Regional Metamorphic Rock)

Basalt with Plagioclase Phenocrysts

Porphyritic Basalt

Basalt with Quartz/Calcite Inclusions

Mafic Volcanic Rock (Fe-Mg silicate rich)

Quartzite (Yellow/Iron-stained Quartz)

Quartzite (primarily SiO2 with iron oxide impurities)

Granite with Orthoclase and Hematite Staining

Phaneritic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)

Granite

Phaneritic Plutonic Felsic Rock

Pink Granite

Phaneritic Felsic Igneous Rock (composed of orthoclase, quartz, and plagioclase)

Gneiss (Metamorphic Rock)

Gneiss

Quartzite Pebble (with Iron Inclusions)

Quartzite (primarily SiO2 with Fe2O3/FeOOH impurities)

Basalt with Epidote Veins

Mafic Igneous Rock (Basalt)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Diamond (Uncut Crystal)

Carbon (C)

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Geode (unopened)

Chert / Chalcedony Geode (SiO2)

Dendritic Agate (or Dendritic Opal)

SiO2 (for Agate), SiO2·nH2O (for Opal)

Mica Schist

Crystalline Schist (often containing Muscovite, Biotite, and Quartz)

Milky Quartz

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt (extrusive volcanic rock with secondary mineral infilling)

Caribbean Calcite

Calcite (CaCO3) with Aragonite (CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Quartz

Silicon dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Obsidian

Obsidian (Volcanic Glass, complex silicate)

Clear Quartz

Silicon dioxide (SiO2)

Limonite (Ironstone)

Limonite (mixture of hydrated iron oxides, primarily Goethite α-FeO(OH))

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Amber

Succinite (fossilized tree resin)

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Lapis Lazuli (Tumbled)

Lazurite-dominated contact metamorphic rock

Green Aventurine (Carved)

Silicon Dioxide (Quartz variant) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O(OH)2)

Milky Quartz

Silicon Dioxide (SiO2)