Organic (If Resin) Or Synthetic (If Glass); Simulating Sedimentary Or Metamorphic (For Natural Stones)

Obsidian

Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)

Quartz with inclusions (likely Tourmaline or Biotite)

Silicon Dioxide (SiO2)

Gold Nugget

Native Gold (Au)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Chert (Jasper variation)

Silicon Dioxide (SiO2)

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

Sandstone

Sandstone (clastic sedimentary rock), primarily SiO2

Chert (Iron-Stained)

Microcrystalline Silica (SiO2)

Green Calcite (often commercially called Green Onyx)

Calcium Carbonate (CaCO3)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Jasper with Quartz inclusions

Silicon Dioxide (SiO2) - Microcrystalline Chalcedony

Orange Calcite

Calcium Carbonate (CaCO3)

Quartz with Inclusions

Silicon Dioxide (SiO2) with various mineral inclusions

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Iron Oxide staining)

Chert (specifically Flint or Common Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone

Arenite (SiO2 based with mineral cement)

Gneiss

Metamorphic rock of high-grade regional metamorphism

Quartzite

Quartzite (primarily SiO2)

Rose Quartz

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

Quartzite

Quartzite (SiO2)

Horn Coral Fossil

Rugosa (extinct order of solitary corals)

Sandstone Chert/Quartzite

Silicon Dioxide (SiO2) - Sedimentary Sandstone / Orthoquartzite

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Yellow Quartzite Pebble

Quartzite (primarily SiO2)

Pink Halite (Himalayan Salt)

Halite (Sodium Chloride, NaCl)

Quartz with Iron Staining

Silicon Dioxide (SiO2)

Quartz Geode

Clear Quartz (Silicon Dioxide, SiO2)

Tiger's Eye (Rough)

Pseudomorph of Quartz after Crocidolite (SiO2 with FeOOH inclusions)

Schist (specifically Chlorite/Greenschist)

Chlorite Schist

Fossilized Favosites (Honeycomb Coral)

Favosites (Genus), Phylum Cnidaria, Class Anthozoa

Chert (Flint Pebbles)

Microcrystalline quartz (SiO2)

Fossilized Honeycomb Coral

Favosites (extinct genus of tabulate corals)

Pink Quartz (Rose Quartz)

Silicon Dioxide (SiO2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Basalt River Stone

Basalt (Aphanitic Mafic Igneous Rock)

Granitic Pegmatite

Granitic Pegmatite with Quartz and Feldspar

Quartzite River Cobble

Quartzite (primarily SiO2)

Agate (translucent pebble)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Limonite-stained Chert/Jasper

Microcrystalline Quartz (SiO2) with Iron Oxides (FeO(OH)·nH2O)

Smoky Quartz

Silicon Dioxide (SiO2)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of Titanium, Iron, or Manganese