Mineraloid (Cryptocrystalline Quartz)

Tiger's Eye (commonly referred to as Blue/Gold Tiger's Eye)

Tiger's Eye is a variety of Chalcedony (cryptocrystalline quartz), SiO2, exhibiting chatoyancy. The blue variety is often called Hawk's Eye.

Jasper

Jasper (Silica-rich microcrystalline Quartz, SiO2 with Fe2O3 impurities)

Red Moss Agate (Jasper)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Jasper

Jasper (a variety of Chalcedony, SiO2)

Moss Agate and Druzy Quartz Carving

Cryptocrystalline Silica (SiO2) with impurities

Chert (or Flint)

SiO2 (predominantly microcrystalline quartz)

Jasper

Jasper (Silicon Dioxide, SiO2)

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Chalcedony

Chalcedony (a microcrystalline variety of Quartz, SiO2)

Banded Chert or Chert with Quartz Veins

Chert (SiO2)

Chert (or Flint)

Silicon dioxide (SiO2)

Carnelian

Carnelian (a variety of Chalcedony, SiO ₂)

Banded Jasper (possibly "Picture Jasper")

Jasper (a microcrystalline variety of Quartz / Silicon Dioxide - SiO2)

Petrified Wood

Silicified Wood (primarily Chalcedony/Quartz, SiO2)

Chert (or possibly Flint)

SiO2 (Silicon Dioxide)

Agate (Dyed High-Grade Polished Slice)

Silicon dioxide (SiO2), Chalcedony crystal variety

Blue Banded Agate (Dyed)

Silicon Dioxide (SiO2) - Variety of Chalcedony

Turquoise

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

Blue Lace Agate

Chalcedony (a form of Quartz) - SiO2

Chert (often referred to as 'Jasper' when red)

Chert (microcrystalline quartz, SiO₂)

Leopardskin Jasper

Jasper (a variety of microcrystalline Quartz)

Banded Jasper (Chert)

Silicon Dioxide (SiO2) - variety of Chalcedony

Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)

SiO₂ (silicon dioxide)

Yellow Chalcedony (common opal or chert variant)

Silicon Dioxide (SiO2)

Green Aventurine

Quartz (Aventurine variety) - SiO₂ with Fuchsite inclusions

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of organic matter)

Red Jasper (possibly)

Jasper (a variety of Chalcedony, SiO2)

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)

Green Moss Agate / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions

Limonite-stained Chert/Jasper

Microcrystalline Quartz (SiO2) with Iron Oxides (FeO(OH)·nH2O)

Petrified Wood

Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)

Banded Iron Formation

Banded Iron Formation (BIF)

Chert

Chert (microcrystalline quartz, SiO2)

Agate (or Banded Agate)

Agate (a variety of Chalcedony, which is a cryptocrystalline form of Quartz); Chemical Formula: SiO₂ (Silicon Dioxide)

Chert / Flint (a variety of Chert)

Chert (SiO2)

Chalcedony (Smoky Quartz or Agate nodule fragment)

Silicon Dioxide (SiO2)

Jasper

Silicon Dioxide (SiO2) with iron and magnesium inclusions

Chert (or possibly Flint)

Chert (variant: Flint)

Green Agate

Silicon dioxide (SiO₂)

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Blue Chalcedony and Picture Jasper Beads

Blue Chalcedony (SiO2), Picture Jasper (SiO2)

Chalcedony or Chert/Jasper with secondary mineral staining

SiO2 (for chalcedony/quartz) with possible secondary copper minerals (e.g., CuSiO3·nH2O for chrysocolla, Cu2(CO3)(OH)2 for malachite) or iron oxides/hydroxides.