Mineral (Or Mineraloid If Microcrystalline)

Agate

Silicon Dioxide / Cryptocrystalline Quartz (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Manganese Oxide Crust on Limestone

Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3

Aventurine (likely Green Aventurine)

Silicon Dioxide (SiO2) with mineral inclusions

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

White Jade (Nephrite or Jadeite)

Tremolite-Actinolite series (Nephrite) or NaAlSi2O6 (Jadeite)

Agate

Banded Chalcedony (SiO2 - Silicon Dioxide)

Jasper (Zebra Jasper)

Silicon Dioxide (SiO2) with impurities

Dendritic Jasper

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Jasper

Silicon Dioxide (SiO2)

Fancy Jasper

Silicon Dioxide (SiO2) with mineral inclusions

Jasper

Silicon dioxide (SiO2) with iron impurities

Jasper (with Manganese or Iron inclusions)

Silicon Dioxide (SiO2)

Dalmatian Jasper (Dalmatian Stone)

Dalmatian Stone (primarily Feldspar, Quartz, and Arfvedsonite/Tourmaline)

Green Jasper

Silicon Dioxide (SiO2) with impurities

Leopard Skin Jasper

Chalcedony (cryptocrystalline quartz) with inclusions

Limonite (Iron Ore)

Limonite (Iron oxide-hydroxide mixture, FeO(OH)·nH2O)

Chalcedony (Botryoidal Agate vein)

Chalcedony (Microcrystalline Quartz) - SiO2

Petrified Wood

Silicon Dioxide (SiO2) - Calcified / Silicified Wood

Gossan with Copper Carbonate (Chrysocolla/Malachite)

Ferruginous Oxide (Gossan) with Cu2CO3(OH)2 (Malachite) or (Cu,Al)2H2Si2O5(OH)4 (Chrysocolla)

Jasper (likely river-worn)

Silicon Dioxide (SiO2)

Limonite Concretion

Goethite-rich Concretion (FeO(OH))

Chert (Septarian Concretion/Nodule)

Microcrystalline silica (SiO2) with carbonate mineral veining

Quartzite Pebble

Quartzite (primarily SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Tree Agate

Silicon Dioxide (SiO2) with Chlorite/Manganese inclusions

Turquoise in Matrix

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

Limonite and Goethite on Gossan

FeO(OH)·nH2O

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Imperial Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz with Mineral Inclusions

Iron Ore (Limonite and Hematite)

Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)

Hag Stone

Porous sedimentary rock (typically Flint, Chert, or Sandstone) with naturally occurring holes

Quartzite with inclusions

Quartzite (SiO2)

Jasper (Mookaite variety likely)

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Jasper with Quartz Veining

Jasper (Silicon Dioxide, SiO2) with Quartz (SiO2) inclusions

Yellow Ochre / Limonite

Limonite (inter-mixed iron oxides and hydroxides, primarily FeO(OH)·nH2O)

Red Jasper (Opaque Chalcedony)

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Zebra Jasper

Silicon Dioxide (SiO2) with impurities; typically a form of Chalcedony/Microcrystalline Quartz

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)