Limestone

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often colloquially referred to as Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Chert Pebble (Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Nodular)

Chert (SiO2 - Microcrystalline Quartz)

Yellow Calcite

Calcium Carbonate (CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Blue Celestite (Celestine) Cluster

Strontium sulfate (SrSO4)

Lapis Lazuli

Lapis Lazuli (Complex aggregate of Lazurite, Calcite, and Pyrite)

Fluorite (Green Fluorite on Host Rock)

Fluorite (Calcium Fluoride, CaF2)

Chert (White Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity

Fluorite (translucent octahedral crystal)

Calcium fluoride (CaF2)

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Black Marble

Recrystallized Carbonate Rock (CaCO3)

Chert (specifically Yellow Jasper variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Lapis Lazuli

Lapis Lazuli (Mineral composition: Lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl,OH)2, Calcite, and Pyrite)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (Nodule/Pebble)

Chert (Silicon Dioxide, SiO2)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (variant Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Chert (Flint/Jasper variety)

Microcrystalline Quartz (SiO2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Celestite

Celestine (Strontium Sulfate, SrSO4)

Nephrite Jade

Ca2(Mg,Fe)5Si8O22(OH)2 (Calcium magnesium iron silicate hydroxide)

Celestite (Celestine)

Strontium Sulfate (SrSO4)

Corundum

Corundum (Aluminium oxide, Al2O3)

Fossiliferous Limestone (Gritstone/Marl)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Blue Calcite

Calcium Carbonate (CaCO3)

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Chert (Yellow Jasper variant)

Silicon Dioxide (SiO2)

Chert (Black Flint)

Silicon Dioxide (SiO2)

Chert (Grey Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in Geode form

Fossil Coral (Rugosa or Solitary Coral)

Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)

Druzy Quartz Geode (Vug)

Silicon Dioxide (SiO2)