Man Made Rock (Sedimentary Analogue)

Granite / Diorite (Granodiorite)

Granodiorite / Quartz Diorite

Chert (Nodular or Massive Variety)

Cryptocrystalline Quartz (SiO2)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jewelry Chain with Blue and Clear Gemstones (Likely Cubic Zirconia)

Cubic Zirconia (ZrO₂), Silver or White Gold/Platinum Alloy

Coquina (Fossiliferous Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Granite

Granite (a plutonic rock)

Granite

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

Goldstone (aventurine glass)

Synthetic copper-bearing soda-lime glass; commonly sold as red goldstone

Chert / River Pebble

Microcrystalline Quartz (SiO2)

Desert Rose (Gypsum Rose)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Pumice

Pumice (Vesicular volcanic glass)

Beaded gemstone bracelet

Indeterminate; likely small polished mineral beads, possibly turquoise or dyed stone, with metal and glass components

Chalk

Micrite (primarily Calcium Carbonate, CaCO3)

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

Carnelian cabochon pendant

Carnelian, orange-red chalcedony (microcrystalline quartz, SiO₂)

Blue Lace Agate

Chalcedony (SiO2) with trace inclusions

Turquoise ring

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; the setting appears to be silver-colored metal

Chert (likely flint)

Microcrystalline quartz, SiO₂

Blue glass-like bead or gemstone keychain ornament

Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

Polished stone sphere, possibly agate or jasper

Likely microcrystalline quartz (SiO₂); exact variety cannot be confirmed from the image

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Slate

Metamorphic Pelitic Rock

Green glassy slag (often sold as “sea glass” or “green obsidian”)

Industrial vitreous slag; primarily amorphous silicate glass, composition variable

Flint/Chert Nodule in Limestone

Sedimentary rock containing microcrystalline quartz (SiO2) within a calcium carbonate (CaCO3) matrix

Polished brecciated jasper pendant

Jasper, an opaque microcrystalline variety of chalcedony (mostly SiO₂), with iron-oxide staining and likely brecciation

Coquina

Coquina (Bioclastic Limestone)

Rough Sapphire (Corundum)

Corundum (Al2O3)

Granite

Phaneritic plutonic felsic rock

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Artificial Rock Face (Faux Rock)

Glass Fiber Reinforced Concrete (GFRC)

Small clear crystal, possibly quartz or glass-like gemstone

Uncertain; likely quartz (SiO₂), but the image is insufficient to exclude man-made glass or cubic zirconia

Yellow cabochon gemstone, likely citrine or yellow glass imitation

Quartz (SiO₂), if natural citrine; visual evidence is insufficient to exclude man-made glass or resin

Polished green-and-black banded cabochon (likely malachite imitation or dyed agate)

Uncertain; possible malachite (Cu₂CO₃(OH)₂), banded agate (SiO₂), or man-made glass

Polished blue-green glassy slag or coated mineral fragment

Most likely man-made colored glass/slag; exact composition cannot be determined visually

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Chalk

Calcium Carbonate (CaCO3)

Granodiorite

Intrusive Igneous Rock

Vesicular basalt (possibly slag-contaminated)

Basalt; chiefly plagioclase and pyroxene, with possible olivine and secondary minerals

Granite

Felsic intrusive igneous rock

Turquoise (likely stabilized or simulated Howlite)

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)