Mineraloid (Human Made Geological Specimen)

Chert (Yellow Jasper variant)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Arfvedsonite in Quartz (also known as Eudialyte/Garnet Syenite variety)

Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2] within a silicate matrix

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz Mineral

Silicon Dioxide (SiO2)

Chalcedony in Limestone Host Rock

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Limonite (with Goethite/Ironstone)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Coarse-grained Quartz with Feldspar inclusions

Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions

Chert (containing Flint and Calcareous inclusions)

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) impurities

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Gold Ore in Matrix

Native Gold (Au) in Quartz/Host Rock

Chert (Cherty Flint/Jasper variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (vuggy variety)

Microcrystalline silica (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Rough Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Quartz (likely Jasper or Chert variety)

Quartz (SiO₂)

Yellow Chalcedony (common opal or chert variant)

Silicon Dioxide (SiO2)

Fossilized Solitary Rugose Coral (Horn Coral)

Order: Rugosa (e.g., Grewingkia or Heliophyllum); composed of Calcite (CaCO3) or Silica (SiO2)

Limonite-stained Granite

Felsic Plutonic Rock with Hydrated Iron Oxides

Orthoclase (Potassium) Feldspar in Quartz

KAlSi3O8 (Potassium Aluminum Silicate)

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Obsidian

Volcanic Glass (comprised primarily of SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Septarian Nodule

Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)

Schorl (Black Tourmaline)

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe3Al6(BO3)3Si6O18(OH)4

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Graphic Granite

Graphic Granite (Granitic Pegmatite), typically KAlSi3O8 (Feldspar) + SiO2 (Quartz)

Vesicular Basalt with Amygdules

Amygdaloidal Basalt

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Chalcedony (River Stone)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Titanium Aura Quartz

Titanium bonded Silicon Dioxide (SiO2 + Ti)

Petrified Wood

Silicified Wood / Chalcedony (SiO2)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Goldstone (Red/Brown)

Aventurine Glass (SiO2 with Copper inclusions)

Banded Chert (Agate-like Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Flint)

Silicon Dioxide (SiO2)

Chert Nodule

Microcrystalline Silica (SiO2)

Borosilicate Glass (Manufactured)

SiO2 + B2O3 (Silicon dioxide and Boron trioxide)