Mineral In A Matrix (Likely Quartz Or Feldspar)

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Ferruginous Quartz

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz (Milk Quartz Cobble)

Silicon Dioxide (SiO2)

Granite

Granite (Phaneritic intrusive igneous rock)

Quartzite with Garnet

Garnetiferous Quartzite (SiO2 + X3Y2(SiO4)3)

Sandstone

Arenite (SiO2 with Fe2O3)

Granite Pebble

Phaneritic Felsic Igneous Rock

Granite

Granite (Phaneritic Igneous Rock)

Granite

Granite (composed mainly of Quartz, Feldspar, and Mica)

Chrysocolla in Quartz (Gem Silica)

Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / SiO2 (Quartz)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Granitic Gravel Piece

Granite (Felsic Plutonic Rock / SiO2 with Al2O3, K2O, Na2O)

Granite

Granite (Felsic Plutonic Rock)

Unakite

Unakite (Episyenite composition: Feldspar, Epidote, and Quartz)

Green Aventurine (Green Quartzite)

Silicon Dioxide (SiO2) with inclusions of Fuchsite mica

Diamond in Kimberlite

Diamond (C in Kimberlite Matrix)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Milky Quartz with Limonite

Silicon Dioxide (SiO2)

Granitic Pegmatite

Coarse-grained Igneous Rock (Granitic composition: KAlSi3O8, SiO2)

Sandstone (Quartzite-rich)

Clastic sedimentary rock (SiO2 primary)

Quartz (Common Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Granite

Granite

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Granite

Phaneritic Plutonic Igneous Rock (composed of Quartz, Feldspar, and Mica)

Slate with Quartz

Low-grade Metamorphic Slate with SiO2 inclusions

Massive Quartz

Silicon Dioxide (SiO2)

Granite

Granite (Silicic Plutonic Rock)

Granodiorite

Granodiorite (phaneritic intrusive igneous rock)

Andesite

Andesite (contains Plagioclase feldspar, Pyroxene, Hornblende)

Rutilated Quartz (likely Citrine or Smoky Quartz with Rutile inclusions)

SiO2 with TiO2 inclusions (Quartz with Rutile)

Quartz (Smoky/Milky variant)

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with fossil inclusions

Granite

Granite (Phaneritic igneous rock)

Glauconitic Sandstone

Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Quartz Vein in Gneiss or Basalt

Milky Quartz (SiO2) within Metamorphic Host Rock

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Pink Granite

Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Plagioclase)

Quartz Veined Basalt Pebble

Amygdaloidal Basalt with Quartz (SiO2) veining

Chert (Flint) with Glauconite

Microcrystalline Quartz (SiO2)

Green Quartzite (Aventurine variety)

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Gold Ore (in Quartz/Sulfide matrix)

Native Gold (Au) in Quartz (SiO2) and Pyrite (FeS2)