Not A Rock (Synthetic Material)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Chert (Pebble)

Microcrystalline silica (SiO2)

Metamorphic rock (for both Nephrite and Jadeite)

Jade (Nephrite or Jadeite)

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2 - a variety of actinolite, an amphibole mineral); Jadeite (Na(Al,Fe3+)Si2O6 - a pyroxene mineral)

Chert

Microcrystalline silica (SiO2)

Limestone

Calcium carbonate (CaCO3)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Lapis Lazuli

Lapis Lazuli (a rock, not a single mineral; primary mineral is Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2

Metamorphic rock

Agatized Fossil or Chalcedony Nodule

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Chert (Jasper variety)

Chert (Silicon Dioxide, SiO2)

Quartz (Milky Quartz)

Quartz (SiO2 - Silicon Dioxide)

metamorphic and sedimentary

Banded Gneiss

Gneiss (pronounced 'nice')

metamorphic

Quartzite and Chert

Silicon Dioxide (SiO2)

Quartzite

Metamorphic Quartz (SiO2)

metamorphic

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Quartz (River Pebble)

Quartz (SiO₂ - Silicon Dioxide)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Sedimentary or metamorphic-derived

Engineer Quartz/Quartzite

SiO2 (Silicon Dioxide with binders)

Chert (Beach Pebble)

Microcrystalline Quartz (SiO2)

Blue Sphalerite (likely dyed or treated Druzy Quartz/Agate)

Zinc Sulfide (ZnS) or Silicon Dioxide (SiO2) with trade-name enhancement

Chert Pebble

Microcrystalline silica (SiO2)

Bauxite

Bauxite (mixture of Gibbiste Al(OH)3, Boehmite ̳-AlO(OH), and Diaspore ́-AlO(OH))

Red Jasper

Microcrystalline Quartz (SiO2) with Hematite impurities

Petrified Wood (Jet or Coalified Wood appearance)

Silicified wood (principally SiO2) or Carbonized Wood

Green Fluorite

Calcium Fluoride (CaF2)

Mica Group Minerals

There isn't a single scientific name as 'Mica' refers to a group of phyllosilicate minerals. Common scientific names include Muscovite (KAl₂ (AlSi₃O₁₀)(OH)₂), Biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH)₂), Phlogopite (KMg₃AlSi₃O₁₀(OH)₂), and Lepidolite (K(Li,Al)₃(Al,Si,Rb)₄O₁₀(F,OH)₂).

Coquina / Limonite-stained Limestone

Sedimentary Limestone with Iron Oxyhydroxide (FeO(OH)·nH2O)

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

Mineral, often a rock given its aggregate nature

Jadeite (Jade)

NaAlSi2O6 (Sodium Aluminum Silicate)

metamorphic

Yellow Jade (often Serpentine or Dolomite)

Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.

Sandstone

Arenite (SiO2 based)

Quartz

Silicon Dioxide (SiO2)

Mineral, specifically an iron ore

Iron Ore / Ironstone Concretion

Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.

Bauxite

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