Limestone

Chert (specifically Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Connemara Marble

Ophiocalcite (Serpentinitic Marble)

Lapis Lazuli

Lapis Lazuli (A metamorphic rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Chert (Gravel)

Chert (Cryptocrystalline silicon dioxide, SiO2)

Chert (Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Yellow/Brown Jasper)

Silicon Dioxide (SiO2)

Amber Flint (Chert)

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Quartz Geode (partially formed/chalcedony with iron staining)

Quartz (SiO2) with Chalcedony (cryptocrystalline quartz) and likely Iron Oxides/Hydroxides

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Orthoceras Fossil in Limestone

Orthoceras (extinct genus of cephalopods) in Carboniferous or Devonian Limestone

Black Marble

Recrystallized Calcite (CaCO3)

Blue Calcite

Calcium Carbonate (CaCO3)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Agate variety)

Cryptocrystalline Quartz (SiO2)

Ferrous Slag (Iron Smelting By-product)

Fused Siliceous Slag

Lapis Lazuli

Lapis Lazuli (A complex rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Fluorite (likely Fluorite on Quartz/Matrix)

Calcium Fluoride (CaF2)

Lapis Lazuli (Low Grade)

Lazurite-rich metamorphic rock ((Na,Ca)8(AlSiO4)6(SO4,S,Cl,OH)2)

Chert / Flint

Chert (SiO2)

Ammonite Fossil

Ammonoidea (Calcium carbonate or Pyrite replaced)

Lapis Lazuli

Na6Ca2(Al6Si6O24)(SO4,S,Cl,OH)2 (Lazurite-dominated rock)

Chert (Jasper variety)

Chert (SiO2)

Chert (specifically Gray/Tan Chert Node)

Microcrystalline Quartz (SiO2)

Malachite

Copper carbonate hydroxide, Cu2CO3(OH)2

Chert (Flint)

Microcrystalline quartz (SiO2)

Chert (and associated river cobbles)

Silicon dioxide (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Chert (Gravel pebble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Fluorite

Calcium Fluoride (CaF2)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Nephrite Jade

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Nephrite Jade

Ca2(Mg, Fe)5Si8O22(OH)2

Lapis Lazuli (Simulated)

Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Nephrite Jade

Nephrite (a variety of the Calcium magnesium iron silicate mineral series Actinolite), Ca2(Mg, Fe)5Si8O22(OH)2

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)