Man Made Material (Metal)

Diamond

Natural Carbon (C)

Obsidian

Obsidian (principally SiO2)

Chert (and Flint variant)

Microcrystalline Quartz (SiO2)

Dendritic Agate (Tree Agate)

Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions

Green Calcite (often commercially called Green Onyx)

Calcium Carbonate (CaCO3)

Chert Pebble (Yellow/Brown Jasper variety)

Microcrystalline Quartz (SiO2)

Coquina

Biogenic Limestone

Tree Agate (or Moss Agate)

Dendritic Agate (Silicon Dioxide - SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Milky Quartz (or Bull Quartz)

Silicon Dioxide (SiO2)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chalk / Sedimentary Limestone

Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock

Chert (Flint/Chalcedony)

Microcrystalline Quartz (SiO2)

Chert / Flint Nodules in Sandstone

Microcrystalline Quartz (SiO2) within Clastic Sedimentary Rock

Chert (variant Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert / Flint

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Milky Quartz (Tumbled Pebble)

Silicon Dioxide (SiO2)

Assorted Semi-Precious Gemstone Crosses

Quartz, Silicates, Carbonates (various)

Chert (specifically Jasper/Flint)

Chert (SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Rough Diamond

Diamond (pure Carbon, C)

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

Banded Gneiss (with Quartz Vein)

Gneiss (Metamorphic rock of varying mineralogy)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Serpentine

Serpentinite (rock) containing serpentine minerals (e.g., Antigorite, Lizardite, Chrysotile)

Silty Sand / Loam

Unconsolidated Clastic Sediment (Silicon Dioxide / Alumino-silicates mixture)

Granodiorite (Gneissic texture)

Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)

Quartz

Silicon Dioxide (SiO2)

Rose Quartz

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

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Lapis Lazuli

Lapis Lazuli (Rock containing Lazurite, Na8[AlSi O4]6[S,Cl,SO4,OH]2)

Chert (Flint variety)

Microcrystalline Quartz (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Chert / Flint (with Iron Staining)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)